Hi @HaPe Hans-Peter, nice to meet you again 
I had not been looking for the SysEx docs on the Montage since we met, for the simple reason that I do not have that instrument. But I recall our conversation where you showed my SysEx was still implemented, and I was happy for that!
Now that you sent me the SysEx, I of course felt obliged 
to have a look at it. Well, one thing is clear: the best hardware controller (I know nothing about software controllers for Yamaha) for a Montage, is… a Montage! This thing is so deep, there is no end to that SysEx !! Some studying will be required to figure out a edit buffer voice dump, that was not apparent at first sight.
A reason some one should make apreset for a Montage would be to control very specific parameters in a gigging situation, not as a replacement for creating a sound. At least that’s my hasty conclusion based on the Sysex doc.
For your SysEx question, I’ll have a look at it later. It is surely doable, but I’ll need to make an example myself how to do it without scripting. I’ll come back to that later on.
Do you have an older Yamaha yourself?
All the best,
Ignace