Cool, Tom, but . . . your wiring diagram shows your headlight-kill relay as NC (normally closed), while the sketch on the relay case shows it as NO (normally open). A relay's NC contacts would be opened by control voltage activation; a relay's NO contacts would be closed by energizing the solenoid.
Or is it just ME?
Have you tested the installation for functionality? If so, I'll hush my mouth, er, keyboard.
And . . . the starter system wiring appears considerably, well, simplified in your wiring diagram, to me.