As far as I understand the Mongoose range:
Expert was the smallest with steel Pro Steel rims, cheaper spider, cranks, and handlebars.
Calis were larger, tri-moly with alloy Pro Class rims(grey hard annodized were released in 1985) and Pro Class Bars and PowerPlate (85+).
Supergoose was Pro-sized, full Cro-moly frame, with Pro-Class rims etc.
Pro Class was Pro-sized with larger tubing than the Supergoose, also lighter.
There were also Pro-Class variants like the Eric Rupe signature and Bill Griggs signature.
I am sure someone will come along soon and add to this.