Good stuff Tinker
I have to add that I use a die grinder with a 1/32" cut off wheel about 80% of the time. The rest is probably a little air saw-all. Of course that is just for CUTTING where a patch panel will butt up (or lap weld whatever you choose). Where ever spot welds are you drill them. On full panel replacment like in late model car repairs about 99% of it is done with a spot weld driller.
Tin snips for fine tuning, like Tinker said, "all the above".
One thing I have to say, you don't HAVE to use the patch panel in it's entirely. This is one thing I see all the time. A guy will have three inches of rust at the bottom and he uses the whole 12 inches of the patch panel putting the weld way up high on the part risking warpage.
Just use what you need.
