Quote - Poser Collission offset and depth are in cm.

Ah. I did not know that. Offset in Mr. Skinner is in Poser Native Units, I think, so my 0.001 Mr. Skinner belt will be 0.262cm, and the 0.0025 one will be 0.655cm. That implies that with the 0.0025 belt, the collison offset should be 0.3 or less.

Yeah, I got mixed up with offset and depth. :) 

Quote - Does the belt has a thickness?

No, it's single sided. The idea was to use this belt only for the simulation, then replace it with something better afterwards.

Even so, there's a limit to how much I can increase collision depth. I'm running tests now with Collision offset = 0.2 on belt and figure. I started Collision depth at 0.2 and doubled it for each test. Going beyond two doublings, where collision depth = 0.8, seems to make results worse.

It's getting late however, so I'll continue this tomorrow, I hope.