A general shim stack tuning misconception is high speed damping is controlled by the high speed stack. That creates the perception removing a couple of shims from the high speed stack will “loosen-up” high speed damping while having little effect on low speed.
Dyno testing and Shim ReStackor calculations show that approach does not work.
Valving Logic provides a dyno test example on Thumper Talk. The rmz250-248 shim stack runs a full stack taper. The rmz250-152 configuration completely removes the high speed stack creating the expectation of “loosening-up” high speed damping.
Dyno tests of the two configurations shows no difference in high speed damping (data points). Shim ReStackor calculations (shown as lines) show the same thing.
To get softer high speed damping while keeping low speed the same requires using a preload ring-shim in the shim stack (linky, fundamentals).