the problem with light spined carbons is total shaft weight is pretty light so increasing the FOC is a good way to add total weight to the arrow. Trajectory inside of 20 yards will be fine for hunting arras, go lighter for target only rigs.
I shoot a GT 3555 at 30" with 100gr inserts and 200gr points...total arra weight is 570 gr ...out of a 57# hybrid, so 10gpp. Thats a lot of weight up front but they fly like darts and I have killed deer to 32 yards with them.
at 8gpp I'd drop 114grs arra weight, so I could cut out the100gr insert and be there, but stilll with a 200gr head. It's all good, but I like a heavy arra.
9-10GPP is not bad at all.I just hate to see folks struggling with rainbow trajectories because of shooting insanely heavy arrows. I haven't kept up with the latest trends in the trad community for the last 4-6 years but there for a while everyone was raving about front loading arrows and weights were starting to get ridiculous for those low poundage bows.