I selected the location based on other builder's photos, but also sat in my seat to make sure the placement took advantage of the full arc of the eyeball vent. As you can see, the angle on the boss was what really made this possible. Piece of plexi to capture and transfer the hole pattern to the inside of the cabin, drill out the holes, and affix with #8 stainless screws. Final attach will need to wait for the 1" diameter flages from ACS.
These are very robust, but they took more time to make than I anticipated (what a surprise). At least I can take solice that I didn't have to make any parts twice!