Rickochet The ones I have, I got before I found the KBS trim charts. I trimmed them like most other shafts, and they work great. KBS shafts do have softer tips, and higher torque than almost all other steel shafts, so they do play softer. I would say the trim(1/2" increments) for an R, plays more like an A.
According to the KBS chart, 4.0 would be the stiffest you could get with the Tour 90 R. The trim I used came up 1" short of their chart for 4.0, so next time, I will go by this chart.
https://www.dropbox.com/sh/zdyiv3e4izy2okt/AAB3GYEAQiTPn0QQzf7FX--2a?dl=0&preview=parallel_trimming_sheet.pdf