I have my arrows cut 1/4" in front of my rest. I have used arrows that go as much as 2.75" in front of my rest.

The most important thing about arrow length is obtaining and maintaining the correct spine for your setup.

IMO a FOC that is over 15% is a waste of resources. At that point, you start to lose a ton of speed. By losing speed, then you lose your longer distance shooting. You increase your #'s of pins and then have to become more accurate in judging distances.