As it now stands, I don't see any egregious errors in the list. If anyone else DOES see any, let's hear about them.
Hey, nobody seems to mind Meguiar's abrasiveness scale, and it has some KNOWN errors in it. We make note of the errors, and as a general guide, the scale is useful. Even a company like Meg's makes a few mistakes, so I'll forgive *us* a few errors.
What's wrong with a list based on the first-hand observation, and resultant hypotheses, of knowledgeable Autopians? IMO, our "guesses" aren't gonna be that far off. Why NOT take our "expert knowledge", combined with our experience, and consider that to be sufficient evidence for a rudimentary guide?
Calling it a "guess" doesn't make it inaccurate

In the absence of evaluative tools not (practically) available to us, an
educated guess, based on actual observation/experience is a good starting point and better than nothing.
I believe our observations could be useful to newbies. I can clearly discern how well a given product abrades my single stage lacquer. And I know plenty of other Autopians are at LEAST as qualified as I am to make such determinations. Am I guessing? Yeah, to some extent. But that doesn't make my observations inaccurate or my opinions worthless. If someone comes up with a different result/opinion, we can discuss it. We're not carving this list in stone
