Any Need To Worry About This Size Fuel/Tool Box In Bed?

So any suggestions on how to cut a metal fill tube to keep the shavings from going in the fuel tank?

I ordered my tank and went with the taller one with a deeper tool box. Who knows if or when I'll get a new toy hauler. Current TT only has a couple years worth of payments made to it and would take a huge hit if I tried to trade it in now because I'm sure I wouldn't get close to what I still owe on it.