I have not had good luck with RV covers. I have a class A RV. The top of the last full RV cover I had rotted within a few months. Now because I am somewhat handicapped I am looking for a rooftop cover...
Not what your asking but ..... I find that a cover that's made of Sunbrella fabric will far out last the Tyvek. My Calmark Sunbrella cover is 11 years old and has been used all but 1 year since purchase. I had the ADCO Tyvek cover prior and it was in poor shape after a couple of years.