It can't be exactly like that. Power for the I lug has to come from somewhere. Power goes in through the S lug, so it either goes from there to the I lug, or it comes from the Starter side as originally drawn.

 

I used a Standard Ignition SS-587, it's an insulated base with one terminal. It works just like the stock 6v one that Ross pictured, works off of the stock push button grounding on the dash.

 

Yes! Thank you for the drawing, I was going to look for a used solenoid and take it apart for a photo but your diagram works just as well. As you can see in your diagram contact with the "I" terminal is only made when the solenoid is engaged and it does not matter which side the battery and starter cables are connected. I will start a new post on why it is always a good idea to use the "I" terminal even on electronic ignitions.

 

The horizontal black bar in the drawing is a big copper washer that shorts across the two big terminals and the I terminal when energized. (Note the bar is where they cheapass on cheap solenoids).

 

I got it now, and it makes perfect sense. Last night, (tired and without glasses) I didn't see the drawing the same, just a broken circuit. Sorry for the confusion and thanks for the clarification. It is just how I pictured it in my mind, but the ol' eyeballs didn't make the connection.