I bought all my covering material yesterday and asked for seaplane grommets. I was advised by the Poly-Fiber salesman to just make holes with a sharpened piece of tubing. He said this will work fine and is approved in the STC as long as it is through at least 2 layers of fabric and has done this on several a/c. I saw them on his Hatz bi-plane and they looked really clean.
Any thoughts on the subject.