How do you get a high FOC % with the proper spine and arrow length?
There are programs out the Archers Advantage, TAP and On Target that will do most of the hard work for you.
Just put in your bow info and what gr head,arrow lenght, nock and fletchyou want to use and they will give you a list of arrows that will spine properly.
But you are not going to get high FOC like SA and myself unless you go to a heavy head 200 + grains, altho you can get there with a 125gr head but you will have to use 100gr brass inserts.