How should I fill firewall holes

[Phungki]

I just made my own with snips and a bench grinder. you can weld a piece of wire hanger to the middle to get a hold of those small ones and magnets for the bigger ones. This is the area I started on to teach myself how to spot weld. A little bit of Rage gold and you are done. It takes a while but it wasn't too bad. I put blue tape over all the holes I knew I would be reusing so I didn't get carried away lol and filled up the rest.