My quick take on actual use of common rituals:  you find the instructions, which tells you what the complexity and effect of the spell are.  The actual instructions should also state what the some or all of the decorations which are required to complete the ritual as if the instructions were the wizard designing the ritual.

  Once you're ready you attempt to cast the spell, you take your sponsor dept and then start discipline rolling to build up your power, with shifts less then your conviction just like normal, and if you're not a caster you'll probably be taking some damage, or paying fate or taking more dept during the ritual to avoid backlash. Then boom, it goes off like any other thaumaturgy spell without actually having to possess the ritual or thaumaturgy power.
A wizard would probably have little to no reason to use common rituals unless it was for a kind of magic outside of his realm of knowledge.

IT might just be me, but I always took it to be that determining the aspects/decorations of a ritual was part of the ritual design and not just done ad hock or done on the fly as the spell is cast, thus the working together or doing mini-scenes to complete the prep, and give it a good narrative feel.

Depending on his Lore an enchanted item that either gives a thaumaturgical effect of water walking can either be done as athletics skill equivalent which should get him where he needs go or places the aspect "water walker" and then he can just invoke for effect to bypass the environmental hazard of 'waste deep in water'.
The enchanted item is probably the best 'rules lawyer' option.

A ritual with a one day duration cast at dawn every day will get you the same results over a longer time and may present your players a way to 'level the playing field' by interrupting it.  This probably has the best story payout of your choices.

If you want to be really cheap, as an NPC you can just give him a supernatural aspect of "water walker" then just pay the fate to invoke it when you need it.  Your fate pool is unlimited and it doesn't pay to anyone as you do it. This would be the laziest way of doing it.

Giving him the 'aquatic' power and narrating it as walking on water and as an extension of his magic is what I'd be tempted to do as a player wanting this effect as it has a good cost to benefit value, unlimited uses per session with no FP cost, as compared to refinement for the enchanted item slot.  As an NPC you don't really have to be a stickler for refresh costs since villains often have negative refresh.

 

My take on the whole 'free will' issue with inhuman characters is that if it quacks like a duck and walks like a duck and floats and flies then even if its not a duck its close enough to count. 

When we talk about free will vs being a monster its not a question of does it have a soul, but rather does it behave as though it does.  A serial killer who can't resist killing is a monster, has a negative refresh and isn't a playable character, but he has a soul.  It could be argued that both Bob and Toot, could be considered as having free will because the both demonstrated the ability to act outside their station or to become something greater then their design. 

Bob does all sorts of actions that look as though they are free will, he takes mister to a strip club and a frat house, he tries to kill his owner when he's evil, he makes a dinosaur eat someone he doesn't like.  He's still tightly bound to his supernatural constraints but he constantly shows he's got wiggle room, like maybe 1 refresh worth of wiggle room.  Toot consistently acts beyond his station, he killed a faerie queen, attacked shagnasty and organized a fighting force, none of which is part of being a tiny pizza loving dew drop faerie.  It could be argued that it was dresden's actions that lead them to all that but the same could be said about Lash's act of free will too.

They might not have free will but they sure act like it.  And just like the serial killer is a monster, maybe these soulless beings have free will. Freedom isn't always a black or white, sometimes is a matter of degrees, and a character just has to be free enough to go above and beyond the call of compels to be free enough to play. If you're looking to have a construct as a character look to these for the Dresden lore surrounding free will and then look to Pinocchio and Dorothy's wizard of Oz companions for creative inspiration.  Maybe your golem who wishes he had free will has had it all along.  YMMV

I keep finding myself coming back to this paragraph in the Falling rules.

The falling rules are not an invitation for super-strong characters and spellcasters to start picking people up and tossing them to a great height, only to fall down and take egregious falling damage. That’s an attack, and the stress dealt by any falling component is already included in the stress of the attack. If your
force-bolt “uppercuts” a guy so he flies up and then falls back down with a crunch of bone, the damage dealt by the attack itself accounts for the “fall back down” part—essentially, in this case, falling is a special effect, a detail of color. Additionally, knocking characters off of high places should have plenty of escape clauses.

Add in the actual mechanics of physically lifting an object up off the ground and you really end up needing a lot of strength, maybe even Super-strong character kinds of strength.

he isn’t really going to be able to move much more than a zone carrying something that’s equal to his base Might. A character can carry something two levels below his Might for a short distance (allowing him to make a sprint roll restricted by Might, with the item’s difficulty as a border value). He can carry something four levels below his Might with no real penalty or can toss it a distance of one zone. Something six levels below his Might could be used as a thrown weapon.

Note the actual movement that you may take during a grapple is only one shift, this means you have to beat the lifting value of the object by 4 to negate the carried item border value.

if you so choose, you can freely make an unopposed attack, movement, or maneuver on your opponent as a supplemental action, which has a value of 1 shift.
In other words, whenever your turn to roll the grapple comes up again, you can automatically choose to inflict a one-shift hit to the target, drag the target with you one zone, or inflict a maneuver (like Tangled Up), and then you must roll the grapple at –1 (the other action you take is considered supplementary because it
doesn’t require a roll).

Remember that +1 to all social rolls against supernaturals is only a 1 refresh power and there are lets say 5 social skills out of 25 skills total, so your math of 5 refresh for a +1 to every skill is ball park actuate. just make the requisite: must be Shonokin. or really just be arbitrary about their skill values and use this to calculate their refresh value in terms of how many shonokin per encounter is balanced.

PS: Dresden lore wise, Demonreach has a limp from the movement of the ice age glaciers and the Erlking reminisced about the good old days of dinosaurs. To be really older then the big movers and shakers of nevernever you need to start predating homo sapiens rather then recorded human history but predating human occupation of North America only needs an ice age or two, which would be much shorter.

Rather then merging skills there are almost enough groupings of skills to want to create columns of related skills, putting all the physical skills in one (guns, weapons, fists, athletics, endurance), social in one (intimidate, deceit, rapport, empathy, presence), and then group the remaining 15 skills into a few groups like maybe (discipline, conviction, lore, scholarship) and ( stealth, burglary, investigation, alertness) et al.

  Then restrict a player to using only one skill column on their skill tree ( meaning only one grouped skill in any one skill rank).  This sort of thing starts to create a more rounded characters but still gives most of the variety that you would want from a diverse skill choice without having goons who cant talk and talkers who just stand there and bleed.  Heck you could even give out more skill points so people are missing less skills but make each column one rank lower then the previous to create a very sloped sort of organization.  You end up with less skills (and trappings) missed while not having to monkey odd trappings together as much.

PS: if your finding athletics to be far to potent, then yank the dodge trapping out, put a 'taking cover' trapping in guns to count as ranged defense, and 'spell defense' into discipline, and then everyone defends like skill with like skill, and then bringing a knife to a gun fight is way stronger truism.

I'm noticing that a lot of these examples are moving very quickly from the realm of surviving an assassination as a single huge ambush hit from a safe distance to what could only be described as a really unevenly matched combat.
Some guy comes at you with two dozen aspects (at least a dozen to get a 24 shift bonus, maybe another half dozen to push up to 36 shifts, and a few for over kill) already in place against you at the start of a combat, you need to run, and hide, and pull out all the stops to make it out alive.  If they don't burn all of them in the first shot, then you get to take an action, its both the way the game works and how time flows.  Game wise, that first hit HOPEFULLY wasn't all tagging and he's spent at least a few fate points on the attack, good news if you survived is that you get those fate points to use in your next defense or even better to spend as Invoke for effects to put something in place to save your ass when you concede, Like help coming to your rescue before you get finished off, or medical help, or any number of random, Life is Chaos, cant take into account every variable type compels to keep your killer from finishing you off.

Setting wise:  From what we've seen of magic in Dresden's world, you really can't cascade a huge set of large thaumaturgies at someone to create an MRSI type casting would be worlds more complex then one big spell.  Whenever we see thaumaturgy in action and even by the rules, the power gets gathered all the aspects get counted and when the last of the power is there, the circle is broken and the spell goes out. 

To do something like 10 - 10 shift hits would mean making and braking 10 circles, gathering power 10 times, and placing aspects on each spell to delay it just the right amount of time to have it all hit at once.  That's a lot of power, aspects gathered or FP spent. 

If you only have one sympathetic link, after its first use you have to spend the FP each additional spell, or have 10 links.  That hands a fair few FP over to your target. Plus most links have a limited usable value, blood dries, hair only works if the matching piece is still on the targets head, etc.  IF you happen to say, light your target on fire, or light your link on fire in order to light your target on fire, then you can't use it again for the next spell.

 The risks of getting compelled during this massive undertaking go up and up every round your drawing power.  Some random thought or distraction and you end up a vegetable, much like Dresden fears the first time he brings little Chicago on line. A phone ringing, a visitor unannounced and boom backlash.  In game terms if you create say 20 aspects all relating to you and your spell casting and NONE of them end up compelled at some point during things, someone is being a lazy GM.

PS: if your GM hits you with a 36 shift attack, out of the blue with no in game warning, and no way you can generate enough defense to live and it simply takes you out with DEATH, then calmly pack up your things, say "That was a pretty slick move."  and shake his hand. Then smash him over his smug prick face with your sack of books and dice, because all he really did was say, " I don't like your character so he's dead." and you probably won't and shouldn't play with such a power tripping clown anyway.