DonM That's probably from testing one sample, though? I wonder if it proves true out in the wild.
Definitely yes that play as the DSFI says. I have used for myself and clients all the FST and FST Pro shafts they play exactly as the DSFI states. I use FST Pro 115's in A flex in Alpha VX irons (TLT Series #6, MoI heft matched 2670 kg-cm2 toe-down) and they play as well as any steel that I have found in the weight range and flex that I need.