RE: Biplane aileron setup
I didn't have enough channels in my receiver to go with all 4 aileron servos separately in my AW Ultimate 50cc, so I went with your option (a). Doing so allows you to still trim right side and left side ailerons separately, as well as being able to program differential throw in the ailerons up and down travel. If you do option (b) you lose all of this capability. I've been wrong before and await someone telling me again. Just my 2 cents. Jon