Longer arrows are not a problem. I have some that are 32.5" with my 29" draw length. They shoot perfectly. It's only important that they spine well.

FOC does not have a correct range. Higher equals more forgiveness. As long as the arrow spines well for the tip weight, you can't go too high.

FOC is not related to arrow speed. FOC is the percentage of weight on the front of the arrow. You can have a 400 grain arrow with an FOC of 15% and a 500 grain arrow with an FOC of 13%. The heavier arrow will drop the most, not the one with the highest FOC.

While hunting, it's easy to know your distances. Don't guess. I'm shooting an FOC of 25% at this time and there is no way I'm missing anything inside of 30 yards - even if I don't know the distance. I've never shot at a whitetail over 25 yards in 37 years of bowhunting.

The higher my FOC, the more accurate I shoot at real long distances.

Personally, I like real high FOCs and heavy arrows. The heavy arrows are probably not quite as important with moderate sized game like whitetail, but I still like the advantages they give me.