You'll really get to like that Cleaveland edge rolling tool! I don't see an advantage to edge rolling the HS skins (except maybe the leading edges that get rolled and pop riveted). Normally, you'd edge roll where one skin lays down over another. Practice with this tool on various thicknesses, and especialy if you're going to use it on an inside corner. As the other poster mentioned, there is an angle that must be maintained, also, I might add that it seemed like you also want to be putting pressure against the edge of the skin...like you are making sure the tool doesnt roll off of the edge. You'll always want to use the edge forming tool before dimpling. The other hint is, less is normally better than more when it comes to edge forming, by that I mean that you can "overbend" and it won't lay down nicely.
I used my neighbor's Cleaveland edge forming tool whenever I needed one (airpark benefit). He had installed a jam nut on the adjustment bolt, I don't know if that's a stock setup or not, but I do recommend doing it. I edge rolled some of the wing skins, the forward top skin (on the sides), and the wing root fairings where they lay down onto the wing. I was really happy with how they turned out. Last tip is, think about how the skin is fitting...some skin edges don't lay down onto another skin on all surfaces, and it looks good if you leave those edges unrolled. Mark the areas with a sharpie so you end the edgeroll in those areas. Good luck!