John:

You should also be able to set it so you can play any RH part from the bottom keyboard. That's what I do with my Tyros/Motif mix. If all the the Motif lead parts are off then I select a Tyros RH voice. Or I turn off the Tyros RH voices and select a Motif Voice. Or I can layer them. All this while the LH plays either a Tyros Style or a Motif Performance. Of course mixing parts from the Style and Performance can also be done but the syncing can be difficult. In any case I play everything from the bottom keyboard ( Motif ).