I want to set up defensive spells in my sorcerer's workshop/business.  Given that I'll be able to pull in about 12 shifts of power (six plus a few other tags), is there any way I can make a day-long spell that doesn't have all teh shifts eaten by duration?  Or should I just renew the things every 1-4 hours?  For Example:
Six shifts of power from me.  
+2 for a hand-crafted model of the store (Crafting)
+2 for mystic carved wooden wands (Lore)
+2 for fine silver wire (Resources)
That's about all I can come up with without using FP's to invoke my own Aspects.  Altogether, I get:
Effect: Six (6) shift maneuver attack with two more shifts (+2) added for duration that puts the "Bound in place" Aspect on target, resisted by Athletics or Might. 
Trigger: +2 shifts
Duration: A couple hours until triggered (+2 shifts)
Effect (

 + Trigger (2) + Duration (2)=12.  Is this right?
By the way, when do such spells take effect?  Assuming the Bad Guy has a more Alertness than me, does it take effect the moment he triggers it (say, pulls out a weapon or crosses a line?)