We chose the Futaba 2.4GHz FASST system to control the SUMO. We have used classic Graupner/JR transmitters together with Futaba HFM12-x transmitter modules and the Futaba T6EX, T7C and T8FG transmitters. The T6EX is not really recommended as you might need to modify it to have a 3 position switch. With the T6EX we also had seen issues because of reduced transmission power at low temperatures (-28°C).
Choose your personal stick mode for the Futaba T7C or T8FG and do not reverse channels. Program the transmitter to have a 3-position switch (for manual/auto1/auto2) to appear on channel 5.
The channels at a Futaba R6107SP should then be
1 Roll 2 Pitch 3 Throttle 4 Yaw 5 Autopilot Mode (M/A1/A2)
Use the radio/t7c.xml radio file for configuration (for a Futaba R6107SP receiver).