Seems to me that you are bypassing the V reg by applying 12V to the field wire. The diagram in your post would only disconnect the starter from the battery.
What is the intended purpose of the disconnect switch?
What should the field wires be? There is a blue and a green going to the alternator and not sure what they are supposed to be measured at...
The purpose is to pass NHRA tech so that the disconnect switch shuts off the car while running. The diagram isn't perfect as that power wire running to the starter also runs to a positive post in the front of the car which goes to the starer relay, other ignition stuff etc..