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Why does Comet recommend (and provide) clutch spring shims whereas Polaris specifically warns against using them?

My Comet clutch came with three shims and I needed two of them to get the engagement right.

I was looking in a Polaris manual yesterday and it warned that shimming the spring would cause clutch cover failure.

Does anyone have any clues why the two companies have such different opinions on the spring shim issue?

I believe the reason for this is called "coil bind", anytime you compress a spring any spring and the coils touch it weakens the spring ,even if it only happens once.Also if it compresses the spring in a clutch to the point of coil binds especially if all the coils bind then the spring becomes a solid spacer, but the clutch is still making centrifugal force and it puts a lot of pressure on the cover,to the point that it could break the cover.
Comet clutches seem to have a little more clearance before they coil bind then the Polaris clutch and are designed the be used with shims ,but it also depends on what spring you use.The yellow green spring coil binds at 1 3/16 of an inch and most other comet springs are spec-ed at 1 1/8 of an inch and can go a little smaller.I hope this helps!!

If I recall correctly, a clutch spinning at a fixed RPM generates the same force regardless of the spring installed or if the spring is binding. The grip force on the belt is the weight force minus the spring force. As the RPM rises, the weight force increases to push the clutch against the belt. As the clutch moves inward, the spring tension increases until the forces balance at an equilibrium operating point.

A Polaris dark blue spring produces about 300 pounds of force near full compression. If the weights produce 320 pounds of force, 300 pounds of that force will be taken by the spring in its tension and only 20 pounds of that force is available to bind the coils. I don't see how an addtional 20 pounds of force could break a cluch cover that is designed to take the force an almond spring produces at full compression (330 pounds).

What am I missing?

What I am saying is once the spring bottoms out it can no longer absorb the centrifugal force as it is a solid spacer, the weights are still trying to close the clutch but it can't so it turns from shift energy to burst energy .I have seen Comet and Polaris covers crack if you put to many shims on a spring like the Yellow Green and others ,Comet even warns against coil bind.