Mark - Was thinking reversible with my design, but like the clean look of the one you show. Do you think that the rear cross member could be cut and all the welding done with the tub still on the trailer? The only other thing to contend with on the 416 is the center tub tab that connects to the frame right in the middle of the rear cross member..could have one on either side added in replace of that one..
Again, wish I could weld...