RE: Too Stiff a spine theory exploration
ijimmy, grip torque is mostly an issue with fixed prong rests. I use a drop away, so it is a moot point.
Also, I do not grip my bow, simply pull it back into the v web of my thumb and forefinger, let it settle where it wants, and release.
Unless you are torquing the bow in the exact same way everytime, your selected spine will react differently upon each shot. I'd much rather work on my form and technique than keep trying new arrows to chase an ever changing problem.