I know my reply doesn't really help, but the FORD and CHEVY Stuff is my ALTERNATIVE to the Jaguar S/C fluid I use in my XJR.
That stuff costs $35 a bottle and it is the same darn stuff you use in your car.
They are all Eaton Superchargers in all of the cars.
T-Bird Super Coupe
I used to own a supercharged 97 GTP and couldn't find a replacement fluid. Although you're getting charged way too much, the dealers up here in Canada only charge $5 per bottle (or about $3.50 US) That GM stuff stinks bad too!
I use Redline differential oil in my GTP. I want to research the absolute best recommended differential oil on this site still but whatever that is is what I'm going for in the s/c.
It's basically performing the same task as a differential and internally setup about the same. I've heard of people using 50 weight motor oil in their s/c, I dont believe its at all thick enough though, nor would climb/cling the gears very well.
GM stuff is expensive for sure and I'm not convinced its the best stuff to use though its guaranteed to work well for all street applications of the motor with regular changing.
As a long time owner of a Thunderbird Super Coupe, I can say that many owners are using Redline power steering fluid with no problems.( recomended by Redline originally). Funny that a GM dealer was charging so much, T Bird owners go to GM for the original stuff since Ford is so outrageous. Eatons superchargers all use the same.