Hello 357max, unfortunately we don't have manifolded gas or mixers, so we need to bring in different gas bottle types when changing out applications. In our geographical area, 90/10 or 98/02 (02 being oxygen) are the two prevalent mixes for GMAW spray or GMAWP transfer. I have run the 85/15 before, but it was probably 27 years ago or so and from a time when I was living in Portland, Ore.
We actually stock the majority of our gas as 75/25 (use it on flux-core and solid wire, short-circuit transfer), then we have some "steelmix", a type of tri-mix gas for GMAW steel, another mixture called "stainless mix", a tri-mix gas for stainless steel GMAW, 90/10 for steel GMAW, 98/02 for steel GMAW, and of course a bit of CO2. This mixture of gases pretty much covers most of the shielding gases that are used in our area. We do try to have the students experience the differences that a change in shielding gas can make. Other times we will intentionally have an "incorrect" gas mixture applied to a particular wire type to show the students what to look for and why a particular gas type might be less applicable or maybe even not be an acceptable choice. Thanks for your reply. Best regards, Allan