fianlly I have my new VFT Extreme, (60#, 80%L/O, 28" D/L) and ready to install Trophy Ridge Matrix sight, no-peep & GKF' s new " short" Power Drop just off the presses and ready to consider arrows, this bow is for treestand hunting mainly whitetail & inside 40 yards and I wanted to try a few different weight carbon arrows, I was leaning toward Carbon Express because they have from CX-7g to CX Hunter-8.4 to Terminator-11g so thought I might try a few and check KE and speed
......my question is what determines what gram field tip/broadhead to use, 75/100/125? 
and what other arrow considerations should I be aware of?
Thanx for the help