Differing gram loads and actuator arm resonances are compensated for through the method and apparatus of positioning z-height of outer actuator arm at an optimal height. Specifically, an actuator arm driven by a closed loop servo motor system for a disc drive system is configured so that the outer upper and lower actuator arms are positioned at an optimum distance, called optimum z-height, from the disc surface. At the optimum z-height position, the gram load of the outer actuator arms are shifted as near as possible to the gram load of the inner actuator arms. At the optimum z-height, the resonances on the head gimbal assemblies of the inner and outer actuator arms are closest.