Joe, I look for coolers that have some sort of slots cut into the sides. Then you can stand it on end and put in shelves to make sorting easier. I made the shelves out of spanish cedar. You can find it in small pieces from
www.woodcraft.com.
Never needed to add gaskets and have no issues with humidity but I also keep mine in the basement so the temp and humidity is pretty stable. I'm up to 4 coolers and so far no nights on the couch, #5 might put me on a funeral pyre of cigars though.....