Re: Tow with cover on or off?
Well my 1st boat did not have a cover, and I definitely prefer with . . . I would not tow with a cover that had any reasonable chance of shredding or coming off. Mine have both fit like a glove.
With that said, the more I think about it, neither of my covers have much contact with the actual surface. If you look at the pic above, the cover stretches from the rubrail to either interior, the windshield or the bow rail. There are very few places where it actually touches gelcoat. The exceptions are definitely the stern corners and the gunnel's "edge". I just popped the cover off on one corner and it is buffed cleaner than just on either side with no color transfer . . .

There
is purple color transfer on my white anodized bow rail, but 409 takes that off.
Oh, oh the plexiglass windshield is a little raggy on the edges, but it has never been bad enough for me to do anything about it.