Steve over at Poorboy's World worked with me through my initial fears of rotary polishing. He would say just go slow and you'll do just fine. One time at one of his detailing events he showed us all how tough it is to cut through a flat panel with a rotary, wool pad and SSR3. It took a lot longer than I thought but he (Well actually Pockets) had that thing literally smoking by the time it cut through the clear. On a sharp edge though....you lose focus for just one second and you can cut through all the clear, base coat and primer in one shot. Tape edges, keep the RPMs at 1000 or less until you get the hang of how it's working then bump the speed up as you gain confidence. As you said it's critical to keep it moving over the paint too.