Hi Futaba

In the 12FG manual, it has a default wing setup for 2AIL + 2FLAP that dictate an 8ch RX.
ch1: ELE
ch2: Rud
ch3: Throttle
ch4: Aileron
ch5: Aileron 2
ch6: Gear
ch7: Flap
ch8: flap2

I have a 4 servo wing model as above but only with 7ch FASST RX. Since my model only does not uses Gear, can I use 7ch FASST RX and select 2AIL +1FLAP wing setup where the FLAP is now CH6. With CH7 empty, can I use Program Mixes to drive the Ch7 to be Flap2?

What would be the step and what are the problem or downside on such?

In my LHS, the 8ch RX is substantially more expensive from 7ch vs from 6 to 7ch which is minimal. And buying 8ch RX is also render ch6 useless in my case. Over here the 8ch RX is US50 more than 7ch RX.