Hi John,
please be sure that the Modulation Wheel is turned fully DOWN (to minimum), because the volume of some voices decreases by turning the Mod Wheel upwards.
If you have connected a Volume Pedal (FC7), you could disconnect it temporarily to check if the pedal affects the volume of the Right1/2 parts.
You can also set the Style Volume to a lower value (e. g. 90 or 80) to have "more power" for the Right1/2 parts. Changing the OTS (One Touch Settings) does NOT affect the current value of the Style Volume.
If a particular voice is "too quiet", you can go to the "Voice Set" and alter the "Volume" and/or "Touch Sense" parameters there. (Please refer to S775 Reference Manual, pages 15/16, for this.) You can save these changes as a new Voice ("User Voice") or to a Registration.
Best regards,
Chris