Keep in mind though, how few vsti plugins were made yet, or any good. Not many. Also, audio interfaces with many stereo input pairs were not as common in people's home setups because of pricing still. Hardware synths running to a patchbay and/or then on to an analog mixing board. They didn't use saturation plugins because they didn't need to. I'm not sure I would try to follow an old workflow all that closely.

 

IMO it's not only about what you use to saturate but also how you patch it.
To form one of the main sounds I like to send it through several parallel chains, for example:

1. direct sound
2. Lowpass -> Compressor
3. Highpass -> Saturation -> Lowpass
and mix that parts.

But it depends:
While a bassline would get all that parallel processing, a lot of (lowend) compression and some rather artificial sounding Saturation, an electric piano would rather get some realistic tremoloed Fender Twin amping and probably lose some transients in the mix.
In the end it's a matter of style, learn some rules and choose which to break...

 

that's for another week, not this week. lol