I have turned my bow down from 70# to 60#. It was shooting 292fps. at 70# and now shoots 282fps. at 60#. What would I gain ( approx.) in speed if I dropped from a 385gr. arrow to a 355gr. arrow? ( this is out of a Mathews Legacy) 29.5 draw. My current arrow is a Maxima 350. Was going to go to Maxima 250.