HI: Alain
I think what you have to do is save your settings to registration memory.
If you want the right hand voice to change at the same time you
change variation's of the style then you will have to setup / program
4 reg. memory buttons.
Then when you get to part you want to change variation & voice
just push the next registration button.

I am not sure but I think the registration memory will call up a
style & load it from the hard drive.(I have not tried this.)
Enjoying the 9000 PRO
Denny