Would or Wouldnt cut

I like the rolling tool, but I wonder how well it will work on a fender well that isn't round like the one in the picture?

not to mention made of real steal instead of a recycled bud light can , my front fenders are rolled but they were done by a pro who shaped a piece of 1/8 flat stock and welded it in along the radius to reinforce the fender , I'm surprised you can't fit a 15 x 8 in back there I had to space mine out 5/16 to get a little more spring clearance for the Nitto 275/60/15s but I have plenty of clearance to the lip still .