Well the original plan of cutting, bending, etc of the electrical box fell through since I realized that the rear down tubes climb at an angle and are not parallel like I foolishly thought. Backup plan :-D
I picked up some 20 gauge steel since I suck terrible at welding 22 gauge with the mig welder and then began cutting. I first cut the back plate trying to match the decreasing width of the tubes. The tube mounting points also posed a problem since they are gusseted in which really jacked with my calculations. After some more grinding and fitting it fit nicely. I have cut 1" strips and started fashioning the sides. I have the sides welded on the box but had to call it a night...plus that sucker is too dang hot for me to be touching.
Please forgive my welds on this one. I had the line speed turned up a little too high at first. It looked and sounded like it was welding fine but when I lifted the helmet the welds looked...well...not to my standards but they'll do. I also welded too much too fast so it warped slightly...rookie mistakes. It's fixable though.
Work is going to be crazy this week but I'll post if I get a chance to work on it some more. I need to recut the bottom piece, weld both the top and bottom in, cut/bend the cover, clean it up, and figure out mounting.