SFRPG-discuss has always seemed to me to be more about established games and settings, or at least where everyone has their own setting and won't be interested in mine. Therefore I suppose that it's not really a place that I ought to witter endlessly about my own setting and the endless process of designing and writing it.
I did set up a group on FaceBook to chat about my setting and where my players can encourage me to write. If any of you are by some chance interested (and [still] use FaceBook), feel welcome to join. https://www.facebook.com/groups/FlatBlack/
But a lot of people don't use FaceBook, and the formatting, indexing, and search capabilities there are less than stellar. Fortunately the munificent Roger Bell_West has generously provided hosting space for a Flat Black discussion category on his Discourse server