Once again most everyone beat me posting a reply.
I think I have tried pretty much every Flex Seal product that Ace Hardware stocks; I can't recommend one of them. A couple of the products seem to work for a little while, but they eventually fail. I feel that the whole product line is extremely overpriced. If I were on the road and needed a quick fix, I might use a flex seal product to get me home where I could make a more permanent repair.
I'm at the point that I want a more permanent repair, not a temporary fix.
I redid the roof on a motorhome last summer. A friend recommended this product. It is great! easy to apply and it sets up perfectly. One coat, no primer, butyl rubber.
EPDM Coatings
https://www.epdmcoatings.com/index.php
Happy camping
Terry