sadams, I see your point. The problem is the way the three panels are welded together. These welds are hidden. So you could either do a lap weld along the seam on the edge of the corner panels, or replace the hole thing.
Think about it, what is the difference between drilling out a few dozen more spot welds to remove the inner panels in one piece. As opposed to that weld along the seam of the panel, I feel the spot welds would be much easier. That would also produce a cleaner job. There would be no alignment to speak of, the windows would fall into place, perfectly.
Plus, you can't do much of a butt weld on that window "frame" outside, because the inner panel is there. You can't get behind the weld for any alignment or hammer welding. Besides, the plan I have is for someone else to do it, not me. Some people may have the skills to butt weld something like that, but lap welding is much easier.
