CC #104 is used for changing player amount in each ensemble player.
At present (Dorico 3.5) we have to manually set this MIDI parameter it through the “PLAY” mode, and this is not managable together with the operation of changin Divisi setups.
(Sometimes I use “change divisi” to turn ensemble string into solo.)
I wonder whether Dorico will have any accommodation to improve the user experience of managing such MIDI CC parameter changes.