the way I understand the concept, those sensors do not only control the intensity of the voice played, but also trigger an envelope each time you make contact.
So what you are asking for would mean to separate these two essential elements.
But to a certain degree you can still control the intensity of each voice-pair with the „SHARP“ knob. And of course arrange voices with the „FAST“ knob and using coins…
Otherwise, I think your wish to control the 8 amplitudes individually reaches a boundary of LYRA that asks for alternative ways of approaching the instrument‘s sound design.