I thought that guy Animal was the one who made it famous? Or was he just the one to popularize the conversion kits? (this period was before my time).
He came a bit later.
First mention I can find online is 1995. It's basically Duchaine, Bill Roberts, Pat Arnold, Bruce Kneller, and a few others telling people about Finiplix, and giving people the general idea how it might be converted. Duchaine mentioned doing conversions on Syvonex, Ralgro, and other vet drugs with Tony Fitton (big strength coach and big early-mid 80's steroid dealer) back in the early 80s.
Conversions of other vet drugs were mentioned in the late 90's, but most people skipped them because they were nervous about getting rid of the estrogen, etc..... Vet drugs are usually AAS and Estrogen mixes (or similar) both to discourage bodybuilders and because those type of mixes cause the best growth in livestock.
Anyway, Basskiller was the first to offer "one-size-fits-all" type kits for the vet drugs and later powders. He sold you instructions, glassware, filters, etc.... at one place. Duchaine, Arnold, and the other guys wanted you to do some leg work, and learn some science, etc...
There was some ambivalence when he first started it, some guys were mad because he was selling stuff that was already known, and not making people learn some of the basic science. Others were like "At least these dummy will have a decent enough guide to it."