Ok, I'm not really pro light arrows or pro heavy arrows. I use both depending on the game I am after and the expected shot distance. These numbers were out of the same bow (60# 28" Guardian) arrows weighed on the same grain scale, and shot through the same Chrono. You might find them interesting

326 grain CX Maxima 280 fps 56.77#KE

497 grain FMJ 232 fps 59.41#KE

171 grain heavier arrow lost 48 fps and only gained 2.64#KE

Dan