Not shure if this is of any help in this specific usecase vs. the OP:
i combine it, mixer volume and bypass control:
i put the mixer control -per channel- on a Fader, on my HW controller.
plus, i add a knob widget.
the knob widget is grouped with the mixer channel control, and mapped to the bypass of the instrument that runs into that mixer-CH.
this is the curvature for the bypass widget
i add then to the mixer control a initial “value set to zero” plateau,
to match the bypass:
this gives an enormous flexibility to run different instruments in one patch,
with full control over CPU load.
Tip: if FX are used specifically for only one instrument,
add them also to the bybass group ! just bypass everything that is not in use.
all handled just by the HW volume control vs. the mixer.
it opens up doors,…but ofcourse only to some certain degree 
do same in a DAW or any other host…haha 