The cycloidal magnetic gear will produce more torque than a competing planetary magnetic gear due to the presence of one air gap and no ferromagnetic pieces. Maximum torque production is dependent on the ratio of the outer to inner ring radius and the eccentricity, or displacement of the inner ring. The 610 mm diameter, 51 mm long gear tested in this paper produces 4122 Nm of torque. The primary contribution of this paper is to detail the field based optimization required to achieve those results, one that also includes the azimuthal span of the magnets. Towards that end both an analytical and a parametric field analysis are employed to reveal the ideal ratio of magnet thickness for a known working air gap to maximize the torque per magnet volume ratio. The secondary contribution is to discuss the best technique for transferring orbital motion to concentric motion, using counterweight techniques to offset imbalance, and bearing load issues.