RE: SBUS programming feature of MZ18
This is explained on page 32 of the instruction manual. You program a device such as the GYA750 at the device, itself, but you also use parameters in the gyro and governor menus of the transmitter. You do not program the device from the transmitter.
We have no information on a fuel quantity sensor, so we cannot comment on it. Whenever, or if, Futaba releases information, we'll know.