BTW, the sliders won’t work as mutes for style parts. Just as volume. So the Part is still using polyphony.

If you have an iPad, there are several apps that allow you to design control surfaces with pad areas, sliders, buttons etc which would allow you to control many things buried in the edit menus, and send sys-ex (like those Style Part Mute codes).

The Roland BK9 Editor app is okay, but it only helps with the Keyboard Parts. To get at those style Parts, you’ll have to design your own layout on an app…