I also have never seen a tank or hood bra (on a car) that did not damage the paint. They are good right off, but either the flutter of the wind, or trapped particles of dirt between bra and fender does it.
I have never had one for my bikes, but had one for my previous explorer, the only good thing I will say about it is no stone chips. The down side, it collected dirt, discolored, the paint, and was a pain to put on. I have also heard from others, that on a bike they flap in the wind and will damage the paint so maybe just keep the tank waxed.
Being an old dirt bike rider, I hug the tank with my knees and cause some scratches. I usually cover that area of the tank with that 3M (or other brands) clear plastic. It works good, the hardest part is making a template so you get a proper shape that does not wrinkle when applied. clear paint protection film | eBay