The idea for the Twidlette is to use the thumb only for modifiers like shift, alt, esc, ctrl, number-pad and use the fingers for everything else.
Here is the proposal
pinky gets 1 key, each other finger gets 2 keys which can be pressed either separately or together. This gives (2x3x3x3)-1 unique chords or 53 unique chords on the fingers. The finger buttons would look something like this:
on the thumb would be an arc of buttons. All but one of the thumb buttons are conventional keyboard modifier keys like alt, shift, ctrl and passed by the spiffchorder to the host computer for processing. One thumb button it a spiffchorder key used in chord creation.