I used a large tarp of the kind used on scaffolding, as an overall winter cover on BRe. Semi transparent, with reinforcement mesh.
This allows you to work inside the boat, with most of the cover still on. Great for when it's raining. Cheapish...
The best padding I've found over the years is that blue foam used to pack around the frames of new double glazed windows for transport. Soft, yet dense. Non sticky. does not hold water, unlike rags/carpet. Wide channel/groove fits right around mast section. FREE!
Far better than any pipe foam.
Lay it along the full length of the mast.
Found it necessary to also pad the outer "girth ropes" (too windy hereabouts to rely on cover perimeter fastenings only) as they too will cut the cover.