I posted a sample here Tracktype as a measure of surface firmness - #47 by Hungerburg - This might not be your average track, I just happened over it on the WE.
I am still wondering, why you want(ed) to make tracktype map firmness only. That way you will start with a dataset that nobody sanely can rely on. I guess meanwhile I got it why bradrh did applaud you: Because tracktype conveys too much more than that. May I remind you: Rewording the documentation into something that meets high standards will not heal “wrong” mappings, and there are lots of them.
That is why I propose to make the documentation match the mappings, and BTW also what is coded into the editors. And if the result is, that tracktype is a “bad” tag, the usage of which should not be “endorsed” - so be it!
PS: From what I have read here in the forum, the most promising post to help this tag to not fail as “a simple one-dimensional classification system for a complex multi-dimensional reality but are either not able or not willing to actually think this through into a consistent and practically verifiable definition. @imagico” I read here - Confused with tracktype usage - #7 by Map_HeRo - I can follow along, can you? BTW: This also does not give you a handy click bait quote that summarises the substance matter in a single readily comestible term. That still remains a job for the values.