Generally you should be able to widen the hole to fit the servos side by side. I would use smaller servos tho such as Hitec 225's. You can add a ply rail to make the shorter servos fit properly.
Generally, unless you are going to rebuild the wing so as to add the servos to the middle bays of the wings, its not really worth the effort with shallow ailerons.
I have never been impressed with flaperons if that is what you are after.