Polyurethane will run if put on too thick, but you can usually sand it out. It does a good job of protecting the project and it looks good too.

I let mine dry about four hours between coats and I would sand the box between coats with 220 grit sandpaper. After the last coat I hit it lightly with 220 and followed with steel wool.

I can't say for certain how polyurethane holds up against glow fuel as I haven't checked it. Whenever I get a little fuel on the finish I generally clean it up right away rather than let it sit there. So far I haven't had a problem.