I need to expand a 3/4" hole up to 1" in order to get the cable for my new depthfinder through the console. I have a paddle bit and a hole saw in 1". I am currently planning to drill a 1" hole through a sheet of aluminum and then screw it down over the existing hole to act as an outside pilot. The question is which bit is better for drilling through the gelcoat without chipping? Does putting masking tape over the spot help minimize the chipping? Any help would be appreciatted.