OK. Try this. It appears the 2 Hand voice patch is geared for the male side of the mouth range. That module named BiqMouth 2 is doing all the formant processing.
It's fed formula A as the main input (on the filled black triangle denoting audio input) that looks like this:
Which says for this input keep the Y axis at zero for the for the first half of the fingerboard (no vocal processing as that will be our pitch input from another formula), and then set it to a 1 for any finger position past half way. 1 means turn on the formant processor in this case feeding it full unity value from the Sub LR output (seen if you travel all the way to the left to see what is actually feeding it).
Now look at the two formulas in the next column labeled D and under that H - in the Direct + row (these will be added to each other and directly applied to set the mouth shape). D does this:
sets the X position from 0 to 1.2. And whatever H is is added to this. Not sure if Ed is moving the BiqMouth through its full range of 0 to 4.8 according to this table (though this doesn't quite match what he says about going to 4.8 - stopping at 4.5 in the manual).
A simple way to get a few different sounds is to simply add a small multiplier in the column that has the D and H in it. I've circled that in the big example above - to the left it says "x" which multiplies what's in the direct column above it. You can just try typing a 2, 3 or 4 where I have a 3. It won't change the stored patch - though if you get a number you like you can save it to a different patch name.
I could have missed something here as I need to fully analyze this patch - but try it and see if you get any different sounds. I'm also not sure how this patch will be different in a full versus half size continuum. I think that is why that D formula kicks in half way but I can't be sure yet.
Can you change the mouth type using the lowest notes on the full continuum? Or is it just a male "Ah" for the lower end of the fingerboard?
Sorry this has no "thereminness" to it. But I'll see if I can modify this great patch to send my theremin into it through the AES input.