I had a lot more on my schedule today then I thought. I'll throw this on the wiki with a writeup eventually but for now - Saturn attached.
Some things I might not have mentioned before:
* Digits which can be any character can be replaced with a '?' character. In Saturn for example, digits 4-5 represent model and digit 6 represent body style. Since most of the models came in only one body style I could use a ? for that digit. Same with trucks, I didn't want to have to lookup the cars weight, and digits 5-6 were descriptive enough so I replaced digit 4 with a ?.
* The example I attached shows the recommended level of detail, obviously it was a bit of work (took me a little over an hour) and could have been simplified to 20 or so lines if I had left out the "Edition" field. So if doing individual Editions takes too much work it would still be acceptable to just identify the models.
Feel free to ask any questions...or point out anything unclear. I'll probably be revising the documentation/How To section based on your experience.