Raising the screws will increase the treble. I believe, and correct me if I'm wrong someone, raising the bridbe side pole pieces will shift th resonant frequency higher and raising the neck side will shift it lower. So if you raised all the poles in the pup you may not be reaching the goal you want. To add bite only raise the poles closest to the bridge. Also try lowering the pup a bit that should add a little more snap and attack.
