May I suggest you look for a more advanced pedalboard?
See, such a device would unwrap the power of your 7600 to an unbelievable level…and wouldn't be so expensive as getting another processor.
MIDI CCs w/values are what you need.
A mod in Vsig could enable an external footswitch to scroll thru the Tweaks but you'd be limited to scrolling thru the logical sequence of Tweaks umbers (1>2>3>4>5>etc), being unable to jump from, as an example, #2 to #9…which is the kind of freedom MIDI gives.
best
I
