I have found Dicor to be a pretty good company, they have a help line you can call. (they have answered all my questions, and in fact have told me how to do it rather than spend big bucks at the dealer). Going on 17 years now and the rig has never leaked How about this idea? Use Dicor self leveling and non self leveling around the edges of the etranabond. Depending if vertical or horizontal.
Then use the Dicor product to cover the roof, etrnabond included. I know their are other products out there. But based on my experience with Dicor, I would use their product. As a thought perhaps watch their youtube stuff and give them a call. My thought is RV's are their biz, they probably know it better than many other companies