Here is what I'm working with. I have both left and right for 67-71 (which I need). The brown primer one can be cut for a patch panel if you have the fabing skills and a welder (which I don't)
For the OP, I generally don't bother with trying to fill holes in sheet metal that has been rusted through anymore; the corroded edges even with rust removed does not weld well, and the whole area tends to not want to take a good weld. I have better luck brazing it up, or backing it up and using filler. Or fiberglass. Or cutting and replacing whole areas.