Gas tank leak

Thanks everyone for the advice and ideas, i will let you know the out come when i get there. I've decided to make a thicker gasket out of cork with no sealant and while the tank is in the car, the last time i took the tank out it wasnt so happy. I am also going to bend the 4 prongs on the lock ring a little more back. Is is supposed to be on top of the prong or in-between prong-bend and the bump?