awshucks

FOC=front of center. It refers to how far forward of center your arrow balances at. Yours being the same as mine is about 20%. You can do it the easy way, mark middle of arrow from nock, [10"] balance the arrow and mark that [14"] subtract 10 from 14 = 4 X 5% [per inch]=20% The rule of thumb for carbons is supposed to be between 11 and 18% from what I've read. I did some experimenting, worrying mine was too high at 20% and reduced them to 15% by screwing 1" threaded rod in nocks [25 gr] Could see no difference in group size to 50 yds. How do yours shoot?
I'm using the same string on my Phoenix and am somewhere between 280 and 290 fps, because the Excel costs you a few fps over the FFF. You can get the advertised speed for Phoenix by going to stock 360 gr arrows and a FFF string, but it isn't worth it in my book. I'm playing w/ 2" Blazers now which puts my FOC to about 22.5% and they seem to be doing remarkable, but the jury isn't in yet, lol. If you cruise the Excal forum, you'll see not many are using the 360 gr stock arrows.