This work focuses on the analysis of the performance parameters of a new magneto-rheological device. Previously, a mathematical model of the actuator head was introduced; however, the complex relations between its parameters made its optimisation challenging, causing the device not to reach its full potential. In this work, the previous model is updated to fit a revised version of the toroidal design, as well as an annular design for comparison. The relations between different parameters are studied to find their trade-offs, and understand how they affect the performance of the actuators. Finally, an optimisation based on an iterative search for valid permutations of parameters, is used to find optimal combinations. Two prototypes are built and tested to validate the results of the optimisation. The study revealed the critical parameters of each design, which mostly depend on the relations between the magnetic flux density, and the active area exposed to the MRF; and successfully optimised the performance of the devices. However, work needs to be done to create a more complete tool with concrete guidelines for specific applications.