Ahem....

Gentlemen,

If you would like to add a second aileron servo to a Tiger II, by all means, do so. Whether you put two in the center, or one on each wing, you will get some very good building experience.

But don't expect great things from the airplane.

Putting a second servo on a 40 size plane is rather "Trendy" right now, because some planes (Mostly of the 3-D variety) will benefit from it. But adding a second aileron servo to a Tiger II will do about as much good as putting training wheels on a tricycle.

Is it sturdier? Yes
Is it needed? No
Will the tricycle perform better? No

Now, if you are looking to do something that will have an effect, and show a noticeable difference, AND, since the plane already has a setup for torque rods, I would suggest trying Flaps (Not Flapperons, which can be more harmful than useful).

They can easily be done by cutting about 6" of the inboard side of the ailerons (the side with the torque rod) and controlled by the torque rods. Then, you can either add a servo to each wing, or use a single servo in the center with flex rods running out to the ailerons.

NOW you have something cool AND functional