Often times, finger pinch can be a form issue. If you learn to take a deep hook and keep it until you hit anchor, it may aleviate the problem.
I used to subconciously roll my fingers out as I drew to anchor. I was basically anticipating my release. It would grind the flesh of my finger in to the back of my fingernail. Very painful and would affect my shooting after awhile (didn't matter what length bow I shot).
I finally realized what I was doing and corrected it by completing my draw to anchor while maintaing a deep hook. I no longer have any problems and routinely shoot my 56" TC out to 31"s. I would suggest however for draw lengths of 30" and longer to choose the 58".
BigJim