Yeah the sight tube is my plan but since the walls are thin, I need to find a way to make sure they are perfectly sealed and will stay in place...from the outside. I realized after it was built and I had drilled the fuel cap hole, that I scrape my hand real bad getting it the tank and I can't make the hole any bigger or the fuel cap won't screw in place. It was a huge PITA to install the aft fitting because my hand can't reach the aft wall. You may notice the other two fittings are real close to the cap for this very reason.