Sorry I didn't get back to you sooner. That is about the same dent I had on mine. I just took it to bare metal and used the premium bondo to fill it, block sanded it and you can't tell there was ever a dent in it..It fell on the trailer when I was on the home stretch when I move back to Ohio for year. Pissed me off, I bought brand new tie downs from Wal-fart and the buckle on it was so sharp it cut the strap. I think I woke everyone up in North Baltimore when I saw it fell....ha
For my tank, black 97 Spirit I used Rustoleum Professional high performance paint and clear coated. It looked good. It doesn't hold up to gas spatter even though when I talked to Rustoleum they said it would so I am going to try the 2 part urethane or epoxy. I see where some out there have gotten good results.