I don't know of anyone making a load range G tire for a 16" wheel. If they did, I'd have some on my dually. They do make trailer tires in G for 16" wheels but you don't want these on your MH.
Being over the tire rating isn't a good idea although you obviously haven't had an problems because of it, yet. In the very unlikely event that a DOT cop ever pulled you over and checked the weight you would likely get a ticket. The odds of that happening are roughly zero.
I currently have my first set of Michelin tires and am very happy with them. I would have gotten the XPS but couldn't afford to spend the money. That would be my choice if price didn't matter. You may also want to look at Bridgestone Duravis. I had very good results with those on an overload truck.