This is a configuration with prioritized navigation keys (arrows and such): Downloads here
Inspired by the thumbless conf, the pinky is responsible for shift.
The other two buttons under pinky are Num/Fn and "modifier".
The combination of Num/Fn with positions 1, 2, 4 and 8 enable quickly typing any number. Press Num/Fn alone for 0.
The combination of Num/Fn with positions F1, F2, F4, F8, F12 enable quickly typing any function key.
The thumb is responsible for Alt and Ctrl.
The keymapping works correctly with the US keyboard layout set in the operating system. For special symbols not available on US keyboard mapping, I've used the Linux specific Shift+Ctrl+u followed by the unicode symbol code. If You have an alternative solution, please share.
I edited the keybindings in .cfg.chords plaintext file (4finger notation). Then opened this file in Twidlit.jar and did "Save As CFG" to get the twiddler.cfg. Enter/Return and the pipe symbol are using the multiple buttons per row experimental feature of Tuner, therefore after modifications in Twidlit, the conf would need to be loaded into Tuner to make these additions.