Sounds good, you're doing the Worm fandom proud.

I assume he builds those shifts while performing other actions as well?

Also, his waves seem to build in intensity over time, so does that mean when he performs his "Ritual" that he also doesn't lose all of the shifts already generated?

If you do make a character with Super Math, I'd be interested in seeing them.

I'd let you take most of Perfect Measurement as a Supernatural Sense, but I wouldn't include the +4 to Declarations.

Calculator Brain and Good With Numbers wouldn't work so well as a Supernatural Sense.

If I ever do then I will let you know.  I'm thinking a sniper with Teleportation or one of the Speed powers.  I rarely make combat monsters but making someone that good with numbers highly mobile with projectile weapons just sounds like a ball of fun.  I have nothing to justify that with though.  Scion of Maxwell's Demon maybe...

High stakes gambler with a penchant for Kennedy assassinations perhaps.

In his downtime he could do completely frivolous things with his power, like tell people the exact number of hairs on their head...

The short story is called Backup.

As corrupting?  Well sure, if for the sake of this argument I started drawing from real life, on which the Dresden Files is a commentary as much as it is a fantastic story then I would have ample evidence.  In the setting from what we've been given?  One example comes to mind, but you would probably dismiss it out of hand since it relates back to what I was saying about fantastic racism. 

The example would be Harry's changing attitude towards ghouls.  At first he's complacent as much as one can be about cannibals because that's just their nature.  When he's exposed to something that changes that attitude he changed gears to indiscriminate hate.  He uses magic viciously, the use of magic reinforces his hatred and he begins changing to react like that with his magic to all ghouls.

Actually, another example just came to me.  There's also his case history overall, for instance when Marcone mentions that he'll take the bet that Harry destroys their mutual enemy.  Harry ends up musing on that, more often than not his enemies end up dead; this would be because he has grown accustomed to using his magic to kill his enemies either directly or indirectly.

No, corruption is a synonym for change, although with connotations for the worse.  Any behavior or use of magic that is repeatable is capable of changing or corrupting that individual to varying degrees.

As for whether or not this is a personal theory, well my evidence for my arguments come straight from the books.  For instance, Harry's anger problems which Murphy confronts him about.  Ok, sure he was influenced with mind mojo to start making his anger more of a problem, but he also realized that it was a problem he had and it was affecting his use of magic and whether or not he used that magic appropriately.  A small corruption, but if it hadn't been some kind of corruption it wouldn't have been worthwhile to Lasciel, and it was self maintaining, and could become worse without further influence on her part once she started the ball rolling.  Another instance, without mind mojo possibly confusing matters, Harry's fear of losing his fire magic, if he failed to use it once it would become harder to use in the future and slowly become impossible altogether. 

An example Harry has noted about wizards in general, if you have magic you tend to start trying to solve problems with magic.  It's behavioral reinforcement.  Using magic is a behavior.  Using magic for destructive ends creates reinforcement for that sort of destructive behavior.  Which is just like saying that killing someone with magic is going to reinforce the behavior of killing with magic.

Or, without the judgement that such tainting is a thing to avoid, 'Will [these results] by magic and be tainted in your soul'.

. This quote applies to -any- repeatable action.  That applies in game or out, it's simply a matter of degrees and whether or not "taint" is the right word.

No the Laws of Magic aren't Laws in the physics sense at all.  You shall not kill is a commandment, it's a restriction on behavior created by the Council, the working of magic in itself has no prohibition against it being used to kill.  So there is definitely a distinction that you're not getting.