I have 220 available, but if I go with 220 then I am not portable, I'd have to weld in the garage, or use an extension cord which would drop the voltage. I wired the entire garage with 120V 20A receptacles and circuits, with 4 20A receptacle circuits just in the garage.

Definitely going with gas. I've seen the damage that untrained people can do with flux core. I see you have a BIG gas tank. How long does a small one last?

Looking at the Millermatic 140 AutoSet...seem reasonable for my needs? Found it new for $699 with a cart.