What I did( Proseal)
I installed mine with the pop rivets per plans, but I put it all together with Proseal and clecoes first, then after the Proseal was set-up, I installed the pop rivets (also dipped in Proseal).I then fillet sealed the area above the frame tube rail with Proseal to match the profile of the skirt skin so there is a finished look and no place for dirt to collect. I cant imagine getting an RV-4 canopy skirt to fit tightly without the rivets and keep the Plexi tight to the frame. Proseal has the bonding strength that I would put up against nearly anything, and is both flexible, and fully paintable. Most folks only relate to Proseal as a fuel tank sealer, but in the world of airliners (my day job), it is used for pressurization ,seam seal, and bonding media. I made the holes through the canopy well oversized, so there is little to no contact between the rivets and the plexi, but the skirt and frame hole size was left at #30 (1/8"). After everything was together, I masked all the inside of the canopy, and painted my interior color.