I emailed Dicor when we bought our camper because I wanted to hear what they had to say in regards to their roofs. Their response was to just use their cleaner every 3 months and nothing else.
In regards to a cover, I bought one from camping world and haven't had any issues. As far as sharp edges, the4 edges we have are the roof drains. I bought 1 pool noodle and cut it off in 3" pieces and then slid them over the drains so now the cover is up against a foam noodle instead of a potential sharp edge.