So things I'd learn.... Nobody should ever hire me for day rate work.
Next up the masking tape approach didn't like that. But did give it a try I think this might just be a bit too complex.
What I ended up doing reverting back to my very first approach and making the two humps separately, then I got a sheet and cut out a template for it with the area for the humps completely removed so that it could lay flat on the original piece and from there I was able to make the necessary bends. Then j finally popped the humps I made on top and welded them in place.
Any tips on taking down the weld at the sides of the humps the flap disk doesn't seem to want to sand it back. In fairness this will never be seen but still