I am following up on this. I still haven't found a wiring diagram that has the same configuration/markings of my switch, which for clarification is a combination headlight/ignition switch on a negative earth 1966 IIa. (The diagrams for the positive earth IIa's that I can find show two different switches for the ignition and headlights, with the posts identified by number: The diagram for the positive earth IIa has some of the same letters that my switch has, but they are not all the same).
My switch has an outer ring and an inner ring. The inner ring has two posts tied together, and is marked "ign." I think I can figure that one out.
The outer ring has the follwing posts on it (they are a little hard to read, but I think these are the markings):
As if you were talking to a 3rd-grader, please tell me what those posts are and where the wires go that are coming to and from those posts. (please understand that I realize these are dumb questions, but if I could figure it out without your help, I wouldn't be asking them).
Thanks for your help.