Is there any default program where there is only one joystick in use, instead of using both? That way there is greater control in the robot.
Yes, read the “Full-Size Robot Controller Reference Guide"?. It describes how the PWM Outputs are mapped and which ones should be use for 1 joystick drive. The guide is on the RC web page under “Description"? at: http://www.ifirobotics.com/rc.shtml#Description