Standard curved bit, I go with curve side toward metal I'm removing, I got pretty darn good and quick at it with as much as I've done. I might get a ripped spot on occasion if I get in a hurry and I also use my spot weld cutter also, but poor folks have poor ways. I'll get a pic of mine
Jerry Tallman 69 455/4sp Windward Blue, deluxe parchment bench seat, under major restoration je_tallman@yahoo.com