i shoot a carbon element at 74# and use 340 fmj. and i have to use a 125 gr head because the arrow is too stiff and wont paper tune. they recomended if i keep using fmj to go to the 400. so if you shoot fmj becareful how stiff you go. at 74# and 125 gr tips with fmjs im still over spinned.
The guy that owns the bow shop I go to (Idaho Archery) has a Carbon Spyder Turbo at 74#, shooting the 340 with same 125 gr head. When we started playing with the my new bow which is at 82 right now the 340 just didn't seem to fly right. Paper turning will continue this weekend when I get back from my work trip so I'll let you know it goes. I was shooting 400's with 100 gr tips with my Z7 Extreme at 70#, they flew great. No way to tell other than "keep shooting".
