...again butt welded the back joint and ground the welds down flush. So as not to have any areas with thin welds, I first welded on the inside a 1/2 inch wide splice at the butt joints. This provided a backing for the MIG wire as I was butt welding the joints..it also prevented blow through holes from being created as I was butt welding.
..the nice thing about getting the NOS inner skirt was that I had the battery shelf support already welded in place as well as some of those wire harness tabs. The swiss cheese holes in the skirt are where I drilled off the horn support brackets and brake booster brackets so that I could de-rust the entire area with te wire wheel. I'll plug weld them back in later.