Hi, not anywhere near being an expert, just picked up our new 245rl yesterday but, just watched a video from grand design recently on this subject. In that he said do not use wax, near impossible to get out of all the lines and rough surface. He suggested Dawn dish soap or another similar product or a RV cleaner that is mild and has a light wax mixed in it. Hope that helps. Like I said, we literally picked ours up yesterday, left dealer with it at 5:15pm. Would love to hear what you end up doing and how well it worked.
Wayne