Two fingers under, three fingers under, one finger over, one under, one over and two under, really doesn't seem to matter as long as the nocking point/tiller is set for your shooting style.
I had this conversation with my fiancee' last evening, while we all desire to have the most consistant release possible, it seems to take care of itself when we set the rest of the shot up.
When I get that elbow in alingment with the arrow and maintain the proper tension(not creeping or colapsing at the shot)I have gotten away with all kinds of crazy things with my release and the arrow still went where I was looking.
I think that we pay a little too much attention to that part of the game.