Clutch shims

After this 1996 zrt 600 being down for a couple years due to not being able to remove clutch from shaft after trying all the tricks. Ended up cutting the shaft and buying a used shaft and secondary clutch. My concern is the shims between the bearing and the clutch. I was able to recover the 4 shims from old setup. And from parts diagrams it shows a .075 and a .030. Question is why is there 4? Any help would be great

Clutch shims