If you cannot get 3.5 degrees rear camber after installing the camber/toe plates, you have another problem. After installation of the camber/toe plates, you should be able to adjust the inside (toward diff) camber plate so that the arm actually hits the subframe. If that is the case and you still do not have enough camber, in all likelihood the rear control arm is bent. These can be straightened by a professional shop but for most the easy button is replacement of the arm.