Major rust repair

[Bill()C]

OK... this isn't really a hard question, but I'm not used to this kind of repair.

I just noticed My 79 300D is completely rusted out under the drivers seat. If it wasn't for the undercoating just hanging there I'd have a real good breeze on my fanny. How my seat has not collapse is a miracle.

I'm wondering exactly how I repair this. I know I get sheet metal... but what gauge and is this a home depot repair. I figure I'd epoxy it to the good metal after cutting out all the bad, sanding it back and priming it.

Or do I get diamond plate aluminum? Also someone told me they've heard of a repair panel made just for 123's.

My problem is this isn't just a 4" whole I'm talking about the entire area under the seat. So bending the metal would be a challenge for me.

Thoughts?

Bill