There's another thread about flutter on a great planes model. They replied with an instruction sheet showing set-up for linkages. basically, the best setup has the link rod connected to the outermost hole on the aileron horn and the innermost hole on the servo arm.
Next best is to have the link-rod on the outer hole of the aileron horn and outer hole of the servo arm.
Completely undesirable is to have the link-rod on the inner hole of the control horn.
Unfortunately, most 3D setups need monster control throws and this is how people achieve them!