[PaulProe]

Put masking tape over the area you plan to drill. Will help reduce any chipping. The location of the hole is critical - measured from the base of the window, not from the hood opening or dash.

When I drill them, I locate the hole with a smaller drill, then go increasing larger till I am at the diameter I want, all at 90degrees. Then I angle the drill and cut on the side to generate the angled opening.

We all have our ways of doing things.

Paul