Great stuff might have a hard time with a 2" gap, I do see they have a "big gaps" version of it, though. You might consider some pipe insulation to push in there instead, or both.
I'm not quite understanding, though, why the bottom 1" of the wall must be insulated but the 4" of concrete floor is fine? Is the floor poured on top of foamboard or ??? I did platon (think drycore) right up to the foamboard and taped that seam.