Best way to avoid water spotting on rvs

Been detailing for a while now but one issue i’ve always had is with water spots. I’ve got a di filter that i use for my last rinse on vehicles to help prevent spotting and then i hand dry with a microfiber towel so no issues there. but when it comes to rvs what is my best approach? i’m doing another rv soon and want to get a good method down so i can stick to it and get great results. also having some issues with the soap i’m using sometimes spotting on the black parts of the rv. i use a ph neutral soap so any way to avoid this too? thank you