i am looking at getting either the new scott exxus release http://www.scottarchery.com/archery-releases/thumb-button-releases-exxus.php or the tru fire hardcore 4 finger.
I own a tru-ball back tension release, which is similar to these just no thumb trigger and mine is a three finger. I tried both out before I bought mine and I didn't use my pinky at all so I went with the tree finger. I would recommend going to a pro shop and trying both out and deciding that way if at all possible.
ya thats what im probably going to do just try a 3 and 4 finger out because i dont think they will have both of these there to test out.