When we bought our Northpoint I bought a brush from my dealer. Really soft and works great, 5 years. A few months ago I was poking around on Amazon and found this
https://www.amazon.com/dp/B01EHD6YP0...ing=UTF8&psc=1
I decided to try it out. The bristles on this one are about as soft as my other brush. I got the 10" one because it's just the right size to fit in a 5gal bucket. A 12" will be too big. I main reason I bought it is because it has bristles on the sides, which makes it nice for cleaning inside corners and up against things like awning arms and such nice. No more bumping the side of the brush head against things. It doesnt leave any scratches or Mark's of any kind on my front cap, the sides of my trailer, or the metal painted lowers.
I also use a higher end wash that it gets after every use and same brand hand wax but it only gets that once a year. Mine has a lot of real estate and takes me 14-16 hrs to do.