Iacas, I agree. I'm not arguing for my wrong answer. Just thought it was an interesting tidbit and, unfortunately, where my mind was at the time.
Birly, I've gone over it a few times and agree that it has more to do with friction than the spin loft. All I can figure is there ideal angle of the club face at impact to generate the most friction, as Iacas said around 45*. And, this is easiest to attain for most people by using a less lofted wedge vs a lob wedge.