I always wanted to try one of these babies, and I'm building a basic one for a physics project right now. However, I don't know whether I should go with a shoot-through or with a roller. I'd like to be able to use it with fingers, by the way. Also, you guys that shoot these, what kind of length and riser length should I be looking at? I realize this is highly personal and based on what I want to use it for, but I'm thinking there should be a general length for bowfishing and just shooting in the backyard.