Gas Tank Leak repair what are my options??

I've used some stuff called Seal All. It works on Gasoline, which was the application I used it in. Problem is you have a open void. If it were me I'd find a self tapping screw bigger than your puncture, get a punch the correct under size for the screw, punch it to make a hole that folds the metal inward for more thread engagement and then seal all the threads and put it in then coat the head. Seal All out gasses to dry so it shrinks and is relatively clear. Or buy a new tank.

Seal-All