I never really thought about it, but I think you just hit on why I prefer an index finger anchor over the middle finger anchor. With the index finger anchor, my thumb is relaxed into my palm and just nestles up underneath my lower jaw. Using a middle finger anchor, it's crammed into my jaw.

Don't know what I do with my pinkie. I totally ignore the poor thing. Guess I'm gonna have to get it a ring or something so it won't feel so neglected.[8D]