I'm ready to install a 4-7/8" gauge in my '32 style steel dash. I've cut hundreds of holes in wood with cutters, but my experience with sheet metal is not pretty. The guide bit wants to hog out and move the hole saw - plus as soon as the saw cuts through at one point it binds up and trashes the cut. I don't want to mess up my virgin dash. Your best ideas or experience is appreciated!