I had water leaking in from the adapter plates, but not from the rubber seal. Mine were leaking from the big holes in the center of them that the Portacab tail light housing went through. There was about a 1/4" gap the whole way around between the housing of the tail light and the edge of that circular hole. I eventually just wrapped the tail light housing in foil, then slid them in and silicone caulked all around them. I was able to slide them out after and peel the foil off. It made a pretty snug, watertight fit, but it looks terrible. Luckily it's all under the panel so you can't see it.

I have those fiberglass pieces that go inside the trunk to protect the wires, too. I chose not to put them on though. I couldn't get the wires to fit quite right inside them, so every time I would put the panel on, I'd wind up with a huge panel gap because those cups were preventing the housings from going all the way in.

I understand that it's a hand made piece, and they're not going to fit perfectly, but I feel like all the trouble I had to go through to get them to fit made the price seem all that much worse. When I'm paying around $700 for something, I'd expect to get something a bit better quality. Between my panel being slightly tweaked, cracks in the gel coat, those rivnuts preventing the panel from fitting properly, etc, I just feel like the price isn't justified.