I fit into the group that does much better with PX vs. x100. There are a lot of ppl that don’t like PX, i think that probly comes down to the stiffer feeling butt section of the PX. When I was fit into PX iron shafts, I was shocked at the difference it made, gained decent amount of distance and drastically tightened up dispersion. I tend to struggle when I feel a shaft has a good amount of bend to it, or has a weaker butt section. I have a moderate/slightly aggressive transition but a late release. I am definitely sensitive to profile changes in shafts.