Nice. One thing I was unclear about on my new Miller Multimatic 215 was how tight the wire spool should be. I cranked it down a little much at first and was having feed problems. It's kind of a grey area.
You want both spool and wire drive tensions to be as light as possible without causing issues. This will improve feedability and extend the life of the wire drive components.
For the spool, you ever so slightly tighten the lock nut (starting with it all the way loose) until you feel a slight amount of drag when rotating the spool by hand. There should be a pretty clear diagram of this in your manual. If it's too loose, the spool will want to spin backwards/unravel/birds nest the second you let off the trigger. You'll see that it doesn't take much tension at all to stop the spool from doing this.
For the wire drive tension, the other poster provided good advice. I know it's different from welder to welder, but on my 211 (identical feed mechanism as yours), I have it set between 2 and 2.5 for .030 wire.
