How to roll a fender lip?

I have one of the Eastwood rollers. They work really well on the front fenders. In the back though the flange is two layers that are spot welded together. That makes the rear flange a lot stiffer and harder to roll. On my Duster I just cut the flange back to the spot welds with a cutoff wheel. It added about 3/8” to 1/2” of an inch of clearance. The rest of the flange is still there and you can’t tell from the outside at all, and doing it that way there’s no real chance of popping any paint or bodywork.