C,It's true the paint is thinner on edges but your thinking of a high speed buffer, not a random orbital. RO's are very safe for paint. I use a 6" foam pad with a Porter Cable 7336 RO polisher. High speed polishers generate alot of RPM which builds up alot of heat in the paint if left in one spot for too long and before you know it, your down to metal if you don't watch out.
Check out the Porter Cable.