Hello Dave! I've read a ton of your expert replies, thanks!
I did this with the trailer hitch plug, 2 pack for $8 on amazon. Great solution BUT it doesn't really keep all the water out at all. I'd have to seal the plastic square trim, but i'd like it to easily come out to use the table when I want, but would love to keep this hole completely dry.
I also have a similar issue with my gas locker lid being waterlogged because the handle relief collects water and during freeze/thaw cycles its cracked the gelcoat and now the whole thing is full of water. I'll be drilling a drain hole through the relief and epoxying, then drilling a hole through the middle of the epoxy once it dries out, so the handle will always drain.
Had it outside in the sun for a few days and in a small room with a de-humidifier over night. These seem to be the only 2 places on my boat that catch water in a way that worries me and is causing damage.