seems straight argon is ok with the silicon bronze wire that is the easy grind stuff
and that wire looks tempting except it seems pretty expensive.

if i were looking for a welder for sheetmetal then i'd look for a mid size mig, miller, hobart or lincoln with the capability to run shielding gas.
something like a miller 175/180/211

cut up some spare metal and go to town welding it back together, figure out how to get a nice spot weld and really figure out how the machine works.