I have been playing with Stu's calculator and am trying to choose between two different arrow set-ups. A 2219 with 165 grain head would weigh 626 grains with FOC of 13.5%, speed of 170 fps and a 2020 with 125 grain head would weigh 558 grains with FOC of 10.9% and speed of 179 fps. The energy is virtually the same for the two. Should I go with the heavier slower arrow with higher FOC or the lighter faster arrow with lower FOC? Also, I wish the calculator had the Arrow Dynamics shafts listed. Any advice would be appreciated.