The covers on my shrouds were tight, and worn out. I replaced them with sizes to match the shroud diameters, but particularly the forward lowers are now wearing where the sheets are in contact with them, I think it would be better to have larger diameters covers that could roll with the sheets.
My previous boat had PVC electrical conduit about twice the diameter of the shrouds and that worked well, until the UV broke them down, but of course you have to dismantle the rigging to get them on.
I may do that for the fwd lowers.
SV Elyse SM437