I would like to buy a gas tank gauge that screws into the spot where the cap goes. I have a 10 gallon round tank. I've seen two kinds that I really like: one just replaces the gas cap completely and screws into place, the new cap has the needle in it and the mechanism has to be removed from the tank to fill the tank. The second kind has its own threads to the side for the gas cap so that you can fill the tank without removing the mechanism. I would like to get either one of these.