Using two ailerons servos as opposed to one aileron servo will usually improve response but the airplane is already set up for two servos. Now using a Y cord for two servos on one aileron channel or using two servos with the second on a slaved channel mixed to the aileron channel will not increase response or feel, There is no difference in that regard.

The differance is using both servos on separate channels will allow for a little more versatility in making fine and seperate electronic adjustments thats all. Also this will allow the use of flaperons which is a really, really bad idea. The use of flaperons will turn this nice handling and easy landing airplane into an awful nightmare to land.

So you see which method you use makes no differance, Oh and your radio must be capable of that type of mix to do it.

John