I've been continuing to work on an Emacs-centric layout for the Twiddler, by extending the TabSpace layout.
Some introductory discussion here: https://babbagefiles.xyz/m-x-twiddler/
And the config file and keyboard maps &c. are here: https://gitlab.com/emacsomancer/m-x-tabspace
(I think it should work on most FW versions.)