I'm not sure if I understood, this rotation bar is supposed to be cleated on one side or the other everytime? I'm not thinking in that degree of finesse yet, but I would take the idea to lock it in the central position when not sailing.
About the mast step ball, what material should it be? mine doesn't seem to be the original one, though it appears to be solid. Would it be wrong to use a brass one? Getting the original might be unnecessarily expensive, since I would have to import it.