RE: Which wing bay?
I don't know that it's all that important which bay you put them in.. but I'll run through my thoughts that lead me to put them where I put them...
Keeping the servos closer to centre will mean less weight out toward the wing tips which means a faster start to rolls and and a more prompt stopping of a roll because of the weight of the servos being closer in.
In the middle of the aileron would be ideal from a flexing of the aileron point of view...probably not something even worth worrying about...
The bays are all the same size/depth, so that's not really a consideration...
Mine are in the 7th bay in from the tip....why?...well, in that bay the servo leads were just long enough to run to the wing centre without an extension....not very scientific is it?[sm=wink.gif]
Hope this helps!