Can't decide which head I should use. All fly great. Killed a bison with the valkyrie head, but no kills with the other two. The valkyrie was amazing on the bison. I have read all the posts I can find, but still can't decide. Some say single bevel, others say GK or Iron will. Tell me which I should use! Thanks 1. Iron will 250 2. Valkyrie Blood eagle 250 3. Cutthroat 250 single bevel Setup: Hoyt carbon defiant 27.5, 77lbs, FMJ dg total arrow weight of 840 gr at 216 fps. All heads fly perfect to 50 yards.