Hi, correct me when I am wrong:
You are controlling the sound levels via gain controls after your plugins, right?
Better you make sure that note on events are only sent to the plugin when needed.
This way when you play a note with delay, the delay will not die when you switch the variation.
I am creating similiar to patch resist with variations this way:
For example 2 plugins: piano and synth
Each is connected to a separate Midi In plugin.
In the Midi In pluging you can filter a note on Event.
This Filter can be controlled by a widget, this way you can
for example filter note on in the 1st variation for the piano and in the 2nd variation you can filter note on for the synth.
Here is an example gig:
VarPatchPersist.gig (29.7 KB)
It is also discussed here: