>>>> Is it normal for BOTH field wires to show 14+ volts or would one field wire show it and the other would not?

Well it seems I missed this point earlier. That does indeed seem odd. I wish I could try on my car, but the motor is apart and the battery out. I also realize that I have replaced my under hood harness some years ago so it may not be fair to make apple-to-apples comparisons with.

It is very interesting that your diode experiment changed the results, and perhaps you are on to something. In thinking about it more and looking at the wiring diagram, it seems clear my previous response is wrong. I'm not certain but I suspect what happens with the dual field alternator is that system (battery) voltage is on one field wire (blue) and the VR alters the voltage on the second field wire (green). It may be the difference between these two voltages which controls the output of the alternator. In a single field, the VR alters the voltage on the one field wire and it is the difference between that and ground which controls the output.

If the above is correct, then you latest measurements on the fields make sense. However, this does not explain why earlier you had high voltage on both fields. The voltage on the green wire should be controlled from the VR; if the VR made that voltage match the blue wire (btw, on my car it is solid dark blue and solid dark green that go to the alternator field), then there would be 0V difference, which I think means the alternator would have no output which does not make sense. Even if the MSD is somehow raising the voltage on the blue wire, I don't understand why the green would also go up. Please don't take any of this as gospel because I am not completely certain.

Is your car a 70? Do you have a 2 or 4 prong ballast? Do you have a dark blue instead/in addition to a blue with white tracer?