EXTERNAL MIDI SEQUENCING
The MNM is able to sequence 6 midi tracks each offering a root note + 3 additional notes thus total 24 in theory. In practice this is not quite true: Midi memory limit is 400 midi notes (single or root) and 192 chord notes.
Using this info, a single step for single midi track can have an astounding 193 note polyphony. However, you can only enter 99 chord notes per step, so the actual polyphony is 100. Using all six tracks you can trigger 5 more base notes so you can get 198 note polyphony.
Well, nobody is going to use all that on one step, so the polyphony is spread across the steps. For example, you can have 4 note chords for every 64 step, and this would make total 64 base notes and 3*64=192 chord notes. You would have still 334 base notes for other midi tracks and they would have to be monophonic because the chord notes are all used for the 4 note chords.
So, the amount of polyphony on Monomachine is a bit unclear by its definition, you seldom max the midi memory out so I wouldn’t worry about it.
Important thing to note is that notes are shared between all the tracks inside the pattern so entering a lot of chords on few tracks eats the polyphony from others. And this limit affects only the Note on-steps. You can still have all the triggerless steps you like for controlling CC and PB.
When sequencing external gear make sure you begin by turn up the note length- for some reason it defaults to 0
— tIB 2009/01/12 00:51