Yes but the mixer volumes are saved inside the style?
It seems that all you can do is change expression.
Also, I dont this that you can do for Variation 1, ACC3
Guitar1 on MAJ and PIANO1 on MIN
on my post this part is from manual:
DAN.,
VA-7 manual p171
------------------------
Expression (control change CC11) is a subsidiary volume
message that works relative to the volume (control
change CC07) message. Whenever you set
Expression to �127� the resulting part volume will be
equal to the value specified for Volume (CC07).
The Volume values of the Arranger parts can be set in
Mixer (see page 112) mode.
--------------------------------
other things you can read are just possibilities of Roland VA-series for styles and are all tested very very long time ago.
again:
you have inside style creator a mixerscreen for:
Expression, Panpot, Reverb, Chorus
you can even record the sliders when you move them(like motorized faders).
and yes they can be saved inside the style on VA-serie and i think you can do even more on G70 and E80.
on Roland MicroEdit you can do many things, So about your example of Guitar and Piano is certainly possible.
unfortunately I still have a persoanal zip disk but no zip drive (no longer Roland VA-76 any more for very very long time now, otherwise you could see examples).