Interesting , so Z and Y are mapped to two different phases ,
so Y more similar to traditional aftertouch? (where you press into it?)
I assume at the point Y is active , Z is full on?!
I like the idea that x, is not initially active too.
I like this, I was hoping ( in advance ) that expressive-e would try to take a different approach to expression, create a unique/different instrument - and looks like they delivered 
initial impressions Im seeing online, seem to be very positive - lots of keyboard players who said they were unsure of the ‘squishy’ Roli feel, seem to appreciate the direction of the Osmosis.
must be a really exciting project for you @Anckorage to be involved in.
I see it has DC input, can it be bus powered too?