What is the best way to shim (raise) rails by up to 1/64 inch at one end of the rail and increasing to 1/16 inch at its other end? I am concerned that a shim at each of the three attachment bolts might not be enough to rigidly secure the rail so as to produce a proper ball rebound. For information, it's a 9 foot Canadian Black Crown with new Artemis cushions. Thanks.