Cable-suspended robots and haptics interfaces are appealing because of their structural simplicity, high stiffness, and high exerted wrench-to-weight ratio. A major drawback is that cables cannot push but can only exert tension. Therefore, actuation redundancy is required; even so, certain configurations and wrenches will fail since they would require one or more cables to push. The objective of this paper is to present the best design for a planar cable-suspended haptic interface with regard to largest workspace with general wrench exertion in light of this cable tension problem. There are infinite designs with infinite wrenches to apply; therefore, the best and worst designs are found by extensive computer simulation given a reasonable quantification of the problem parameters.