DSDP Don,
That wrap material is something that I would be interested in!
I have the Coastline Car cover for the Honda but don't use it much anymore, just too much trouble, especially, when it's dirty. I found that it does scratch the paint a little so I use the 'blue' painters tape where the rubbing occurs.
Our rear mud-flap is non-flexible and is positioned at the very rear just under the bumper. This set-up seems to work better to keep the rocks at bay from hitting the toad. We do have a couple of rock chips on the bumper and at the edge of the hood on the Honda but I'm not sure it didn't happen just driving it on the interstate without the motorhome.
Safe travels,
MM.