I made the skirt so it would support a shoulder rotation. In order to do that it had to be modified to accept a 23″ Rocklear bearing with supports for motors to drive the gears rotating the shoulders. I also added a section of 4″ diameter Schedule 40 PVS tubing to hold the control head. Also, with the flange on the bottom of the skirt, I inserted flush screw mounts and used wing nuts to hold the the skirt to the base. Then came the work for the dalek bumps. The best ones I used were from EBay store Zophieschoice. They are the best 4″ partyfavor balls.