I welded a couple chunks of angle iron on my rollers to let the pipe slide on no matter what size it was. No more dimples then.
I also cut the sides (under the rollers on the stand itself) open to allow a bend out of the side of another bend.
Roller placement is crucial to a decent bend also.
Pipe quality is key too. Shitty home depot pipe will split where better pipe will stretch and shrink alot more before becoming deformed.
Keep the seam on the side of a bend. If the seam is inside the bend it will wrinkle. If its out side the bend it might split. If its on the side of the bend then the seam doesnt stretch or shrink when bending.
