Your follow through should be equal to the distance that you pull the cue back before following through.
Scott,
A pendulum swings the same distance forward as it does back. This is a natural motion, which when duplicated as a stroke in pool, usually yields the smoothest motion. It's the exact same for all other sports. Tennis, golf, etc. The backhand swing is equal to the follow through, as that's the natural distance the body needs to slow down the follow though.
No. See:With enough force you can overcome any throw factor for the shot, right?