RE: Programming switch "C" on a 9C ?
What I think you might be looking for is an Offset mix.
I recreated your set up and then added two offset mixes with Offset as master in both, and Gear and Aux1 as slaves, I set this to around 20% with Switch C in the Center postion.
Sincerely,
Krysta
Product Development & Support Specialist
Futaba Service Center USA