Tracking scale, I think is the sensitivity you see in the GUI for settings of a parameter. It's the sensitivity of the "dial". I don't know of any official documentation on any of the file formats. There are people who've written editors that certainly must know more. But I'm not sure if any of them are still involved with Poser and where they got their information from.

I would sure like a wiki of what does what, and (better, maybe) how to do X with Y. I've been using these:

http://docs.daz3d.com/doku.php/artzone/wiki/user/rbtwhiz/technotes/content/erc/start https://www.renderosity.com/mod/forumpro/?thread_id=2735605

And over at SM forums, there's talk of the need to preserve the data in their retiring Poser forums, specifically because there are so many gems in them. I could certainly host a wiki. And I've already probed their API to find that I can dump entire threads as JSON, which is easy to load into any database and present however.