Finished cutting the rust out but remembered Volcom saying to fish-mouth the welds so I cleaned off more area to do that tomorrow. Or instead of cutting out a wedge on each end, could I make the patch panel have the wedge?
The fish mouth recommendations were for a plate being welded to a frame (steering box, scabs for sliders, etc....). For that damage you cut out (which looked good for cutting it out with a cutoff wheel!), just make a plate to fit the hole and weld it in. Then take some diamond shaped plate and weld them over the vertical parts on the patch you just welded in the frame.