As for the Al skills, I can TIG but prefer the spool gun when I can get away with it for a few different reasons. Here is another battery tray I built for a buddy's KK. It goes under the bed in the stock battery compartment and holds 2 lifeline batteries of obsessive size. They are held in by straps. The middle section is hinged and houses the inverter, charger, circuit breakers, plugs, etc.
Nice looking work. BTW you have more welding helmets than I have pairs of shoes...