GM 3 Wire Alternator

[Cavalry]

I put a GM 3 wire internal regulator alternator on my Kubota and am having some problems getting it to charge and use the idiot light. I have no problems using it without the light.
It is hooked up like the first diagram. Light will stay on, alternator is not charging. If I momentarily give the sense terminal 12v it will charge and keep charging. My thought is the bulb has too much resistance and can not break the threshold to start charging but once it does its fine.
The second diagram shows a similar system with a resistor added to prevent this(and charge with a blown bulb). I cannot find the value of the resistor or a minimum resistance to start charging.
I have found a lot of references to using a diode, but since this is a diesel I really don't have to worry about electrical run-on