I drilled the holes for the OHC eyeball vents and then test fitted the vents. I didn’t have a real good way to drill these 2+” dia holes. I tried a hole saw first but and it worked, but it was really a bit too large. So I opted to trace a circle and use my Dremel with a spiral bit to cut the holes out slight under size and dressed out to final size with a file.
I then located and drilled out the holes for the reading lights and associated switches.
