Thanks for getting back to me.
The behaviour I am hoping to achieve is that, when I press Recall, each of the bit change buttons is set, the sysex knob moves to the corresponding new value, and the sysex knob sends the new sysex string to the synth. At present, the first and third part works, but the sysex does not update. It was not clear to me whether the sysex knob should be a subcontrol of the Preset knob. I tried with and without to no avail.