Orville can't store wet/dry mix levels per preset.
-use an external mixer/splitter to use Orville in parallel, at 100% wet.
-use MIDI CC to set wet/dry to a specific setting. No need for a pedal. A set value can be sent w/the MIDI program change from the pedalboard, if it allows to do so.
-modify presets in Vsigfile to add internal dry/wet paths and balance control.