I think you pretty well have it right. The outer switch with the "handle" is for lights only. A click clockwise from off gets park/tail. A click CCW gets head and tail but I don't think it should get park lights. The key is only for the coil. Vertical is off and turn left for on. I am going from my wiring diagrams here rather than memory. The contacts on the back of the switch are labeled B for battery (NU, that's Brown/Blue, wire from the regulator), S for park (side lights in British speak), T for tail light(s), H for head lights, C for coil (white wire in the center) and A for auxilliary (seems to be common with H contact). Hope this helps. Also, protect that switch with your life if necessary. It seems to be unobtainium unless you can find a parts car.