I also use the foam pipe insulation (looks like small diameter pool noodles) which already has a slice in it so it fits or piping. Home Depot, Lowes and just about any hardware store sells them for about a $1.00. They come in 6' lengths. They envelope the entire blade and keep it off of the window. When I park at home, it takes me about two minutes to slide them and the mirror covers on.
If you're looking for something nicer looking while staying at a long term spot in a park, I would probably go with the custom wiper covers.