The control horns would be the same type used on the elev/rudder and could be at locations B or C although I like B best. Servos would be directly forward of the horns. You would want the linkage to come off the inboard of both servos OR the outboard of both servos. That way, one aileron will go "up" while the other goes "down". Don't need to worry about differential but it could be used if you really want to mess with it. First step is to get it working at all which isn't hard at all. Need to beef up 2 adjacent ribs slightly and install servo support beams or platform between them.
RCKen or MinnFlyer both have great illustrations of all this available of course. PM either of them and request same to be posted in case they miss this thread