how to roll rear fender lips

You'll have a hard time just rolling the whole quarter lip. Remember that the quarter lip is doubled up, it's the quarter and also the wheel tub, and those are spot welded together for the entire lip. The spot welds are about a 1/2" in from the edge. What I would do is located the spot welds, then trim the lip down to the edge of the spot welds (so the tub and the quarter stay attached), and then fold the lip over from there. You'll need to use a hammer and dolly to keep from distorting the quarters.