Opening Cast Aluminum Valve Covers for PVC Grommet

I didn't like the idea of hitting the plug with a hammer either so I used a hole saw the size of the knockout. But...... the grommet woud not fit so I had to take a little off at a time with a dremel tool and a round file until the grommet would slide through. The whole process took me maybe 20 minutes. Works fine though, no leaks. I also installed the baffles that MP sells which helps prevent leaks.