Do any changes have to be made to the pay-on rollers, to avoid the
lighter rope slipping and potentially overheating locally? On our
winch, the rollers are heavily scored where generations of steel cable
have slipped a bit and cut into the surface.

These rollers are now about 40 years old, maybe older. While they could
perhaps be renewed with a good surface, they do have considerable
inertia, and a free-running cable suddenly coming into contact with one
of them is bound to take some time to whirl it up to speed. Steel
stands up to that - would Spectra/Dyneema?

Chris N.