Chipmunk,
My contraption does do the "roll," or "flare" on the inside. I turned the inside nut sort like a lug nut, but with more of a concave to provide something like the original installation. I did manage to mar the paint a bit around the outer exterior (it did buff out, and it is a 10 foot paint job of my own doing so no big loss), but that's because the rubber pad I used is too big in diameter. It's a "one off," and I have only installed one ferrule, but it worked.
