Through the hard cover

Just an FYI: I do NOT recommend this method! PITA if you have any issues. Go through the rubber cover.

Make a template that is 7/8" in diameter and trace with a permanent marker. Or put a nail or screw into the center of the circle and tap it so it leaves a dimple -- that's where you will drill. I used this location because it gave me the most slack in the wiring. The shop that does this recommended not putting the gasket in the center of the hard cover because there wouldn't be enough wiring slack.