I have a 20 cf bottle of Tri-Mix (91% Helium 8% Argon 1% CO2) that I got for using with MIG welding stainless. Is this usable for TIG, any benefits of this over 100% Argon?

I think I can get full credit on the bottle if I trade it in, would any other mixes (helium/argon) or gasses (helium) be good to have on hand? Or maybe I can get a transfill pigtail and keep it as a backup/portable unit for Argon.

FWIW, I'm just getting familiar with TIG on (stainless) steel now, I'd like to do aluminum projects, and maybe even some copper.

Rob