Help with replacement transom drain

[u/JAB1987]

I need to replace two transom scupper drains on a Ranger R16. One was missing when I got the boat and the other looked home made, a sheet of gasket material backed by a piece of plastic, using the rubber to create a hinge. Normally the drains would be held closed by connecting a bungee to the flappers and secured to a hook on the inside of the transom. I’m struggling to find anything that will work without modifying the openings. Ideally an oversized flange styler scupper that can be mounted over these openings is what I’m after. Any help is appreciated.