I do not want to put anything on my roof that I would not put on my paint, because you will get some run off, even if you have gutters. I don't know what some people use on thier roofs, but I've seen some awful run off staining, and it's more than just from roof oxidation.
I hate heights and really don't like being on the roof of the coach one bit...... The first time I thought I would use my automotive car wash and a pad on my extension handle, but it was just way too slick for my comfort..... I ended that session very quickly.........
New method is using several foam rubber pads I move around on, sit or kneel on one, then move the other 2 as needed to get around. When I did my first heavy scrub down of the roof on our coach about 8 months after we got it, I played Cinderella, took a bucket up on the roof with clean water, and a bottle that my wife makes up that contains baking soda and peroxide. I simply scrubbed down a small area at a time, then wiped it clean with a damp "rinse" cloth. Just work roughly a 2'x2' section at a time. Took about 3 or 4 hours, but came out very nice. (Required quite a few bucket rinse outs and fresh water refills).
Since then, I have just rinsed it off with water a couple times (standing at the back near the ladder on my pads, and just spraying it with a hose), and then recently did a hands and knees wipe down with a very diluted all natural cleaner, and it looks fine. I do need to clean up the dicor a bit when I decide to get serious on the roof again.
Another safety idea is to work with your slides and awing out........
2015 Tiffin Allegro 31SA, 24k chassis
2015 Jeep Cherokee Trailhawk