I finished my platform today. It is more crude than I had wanted, but better than I expected. It is a simple plywood thing with cutouts for my recessed wheels, which happen to be 3.5" in Diameter. Tomorrow I drill the platform for the tail wheel, and too accept the stepper mounts. Circuit board mounts have not yet been determined, but the battery carrier is also to be mounted after drilling. Rear docking sensor mounts will also be installed.