We have an aluminum boat and last year we added some chairs to the bench seats. We bought the square flat swivels from walmart. Mounted those on the bench seat with toggle screws. Then added the chairs. It was a pain to get those screws tight! Not much room to work! Anyway, this year the toggles are coming up. So, I think we need to add a piece of wood to the bench and then the mount and chair to the wood. My question is how do you add the wood? The aluminum is really thin. Go from the sides? We don't have a rivet gun. Or could the wood be glued down? Thanks for your help!