Nobby,
You missed my point entirely! I NEVER use auto chords from the right side of the split. I need the harmonizer to recognize the chords (right handed). If I use the arranger, it's always left hand, but I play full chord patterns in the right anyway - just as if I were playing with a band.
I don't think the Yamaha can do a "right hand only" arranger trigger, but it does a great job in FULL kb mode.