I would recommend pulling the fuel tank out and replacing the blind nut or nuts as necessary. Once the fuel tank is out you should be able to see the nuts on the back of the firewall and pushing them out isn't really that hard. Then put a drop of epoxy on the new nut and suck it into the firewall with the new screw.... I had a nut spin and had to cut the head off to get it out....stripped would be a much easier repair I think..... Good Luck

Ryan