Use case question

[Corky]

Good to see you back!
This may not answer your question, but I thought it might give you some ideas:

Trigger status change with Transport

OK, one step at a time: create song states in Cantabile for the different configurations you need over the course of the song (you need Cantabile Performer for this!). The first state may be configured to play a piano, the next to play a Hammond, etc. I am assuming you know how to use song states - if not, see @brad’s excellent tutorial videos create a MIDI track in Reaper or any other DAW that has nothing in it but a specific MIDI command at the times in the track when you want to change…

Trigger status change with Transport

See here: Sneak Peak - Transport Triggers