thats funny- we just checked one last saturday--the above post are correct 60% at best!! i think the comb "up" equation is for every 1/8" = 4" at the rock when shooting at the 16yd line (30yd shot) correct me if i'm wrong?
one more thing- just for the heck of it- we put a bore light in the 90t low rib, comb flat- at 23 feet, the red borelight was barely 1/2" hi above what we were aiming at! do the math on 30yds equaling what the poi wud be?
ps - why 23'- becuase thats the width of my gunroom!
my 301 which is 100% hi , measured 5" on the same spot
If your 90-T has a factory adjustable stock, there should be a couple of set screws in the upper hardware. The diameter and thread is 10-32. This means for one full turn on each screw, the comb can be adjusted 1/32". No need for a zillion different in thickness spacers.