Millermatic 200

I got the Miller! It's a Millermatic 200 made in 1987. The gun has been replaced with a Tweco Model 2 15 footer and it's setup with.030" wire. It came with a partially filled Argon bottle and a regulator/flow meter. I got the whole setup for $500. Craigslist Rocks!

I need to get a different plug installed to work with my 220 outlet and the gun is missing the gas nozzle and insulator. Luckily parts seem to be readily available for the Tweco gun.

From what I've read, .023 wire is best for sheet metal. Is this necessary or will the .030 that's in it work?