Who owns the finished collar's appearance acceptance now? Start with that person and actual samples. The gripper supplier can propose contact changes, but the new process should not invent its own easier standard
Have them agree the viewing conditions and retain representative samples, including the faint bands, before asking the supplier to demonstrate an improvement.
Use those to plan a paired trial, with each collar checked before and after. Untouched neighbours give useful background, but they cannot tell you which marks were already on a specific handled piece
What does softer mean in their proposal? I would want an identified pad material and geometry, not a sample of something pleasant to squeeze that nobody can reorder when it wears.