Hello, I bought a used xmt 350 cc/cv including a wirefeeder (Miller S-22P12).

I want to get the most out of it, including tig and alu welding.
I read somewhere about mounting a gas valve inside the xmt, is this oem parts only, expensive?
I also read about the spoolmatic gun, is this the best solution for alu, or is it better with a push pull gun?

What about the optima pulser?