Thank you very much for starting this discussion, posting the code, making the video, etc. For the record, I think using Libreoffice Calc as a presentation tool was inspired.
As a relatively new Stump user I've also been curious about groups. The 1D list of groups has felt limiting compared to previous WMs I've used that supported a 2D grid of workspaces (and so far have been too lazy to write functions to do the appropriate modular arithmetic to simulate a 2D. Now with your code we can go 3D—even better!). I think you have an unusually window-heavy workflow, and other ways of skinning the cat include having a lot of buffers in one Emacs, browser tabs, terminal tabs, perhaps tmux, using multiple monitors/heads, using splits (back when I had a 4k monitor it was almost necessary to use splits to make windows a usable size), etc. I personally have a group called "messaging" with five or six apps in it (Signal, Slack, Element, etc.) and am happy to use C-t <n> (0 through 5) to get the right one up.
FWIW, I have hotkeys to cycle between groups and move windows between groups. I completely forgot about the C-t F# bindings and don't plan to use them.
Anyway, that's my answer to how I deal with group management and I'm very interested to hear how other people approach it.
—Tim
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Tim Macdonald