After finding the answer to the buring question, "How does one dimple for a 4-40 screw?" I was prepared to complete the mounting of my AOA ports for the Advanced Flight Systems EFIS. I placed the two units at 17% of the wing chord (255mm from the leading edge) and inboard of the 7th nose rib by about 6 inches on top and 9 inches on bottom. To seal the units, I used Permatex® Ultra Grey® Rigid High-Torque RTV Silicone Gasket Maker. Before I close the wing up, I'll probably go around the edges with E6000 Industrial Strength Adhesive to lessen the chance of any future air leak. I'm really quite sure these units are secure and air-tight, but it's easy to double my protection now. A fair amount of the time for this task was spend in removing the clecoes from the nose skin and spar rivet line by strapping down the whole wing again and gradually loosening it to avoid "smiley's" in my nose skin. As far as I know, I won't be strapping down the wings again until it is time to rivet them shut.
Wing open showing upper and lower AOA ports as installed
Close-up of upper port with drain
How it looks from the outside. Note the super fine hole between the two mounting screws.