You are correct about that Paul, thanks. but I haven’t been able to find away to use expression maps effectively - except in the simplest of situations.
In this case the problem is that, ideally, I would like to playback more than one type of trem articulation (‘normal’ and sul pont). Both instances require the use of trem notation - so at least in one case the wrong type of trem will be triggered if I use an expression map. (This issue is much more acute with, for example, staccatos - because there are usually loads of staccato-type articulations to choose from.)
I have tried to use expression maps by creating ‘playing techniques’ that are no more than key-switches - labeled KS12, KS13 etc. - but I’ve never really been able to get this strategy to work reliably enough.
As it is - I find having an additional hidden staves for key switches works quite well and also lets me access various other playback mechanisms that some libraries use.
Best wishes, Ian