At the risk of going against the grain here, I've never worried about FOC unless I was building an arrow for Field Archery (out to 80 yards),FITA (out to 90 meters), or if I were building a hunting arrow with a fixed blade head. I do feel that FOC has it'sbenefits when your shaft will likely see windy conditions on long shots, and also when you have a broadhead on the arrow, but otherwise I don't worry about it too much.

My current arrows are just short of 9% FOC and when I'm on I'll wreck at least a couple pin nocks per practice session at 50 yards. In a 50 arrow practice session at this distance I'll miss a 5" spot maybe 2-3 times.