I had to make the 2 x small F-721-D attach angles again as I drilled the platenut in before checking fit. No big deal, made them, drilled the holes which attach to the canopy deck and then marked the panel hole onto them and drilled out the hole. I purchased 2 x new 'Steinair eyeball vents' through 'Aircraft Spruce' as they look great and open and shut the air better than the stock plastic Van's vents. So it was a matter of making up the base for them to screw into. Piece of scrap cut 3 1/8" square, cut out the hole for mounting, I riveted the angle to the square plate and placed in position, looks great.
