[Coley]

Actually, I think there are 2 different voltages that apply to these ignitions.
One is the voltage that is supplied 'up to' the coil, as you mentioned.
The other is the voltage 'across' the coil...which is lower due to internal resistance.
Either way, Pertronix states that their units will run well on a voltage range of 8 to 16 volts....and I am within that now.
Previously I was down just below 5 volts (without the alternator adding voltage)...and that was what caused 'cut out' at low speed.

The update tho'....right now, ba-da-bing, starts up great in the morning...2-3 pumps on the gas, starts right up and goes to choke/high idle....I head out within about 20-30 secs.

Overall tho'....its a great exercise to go thru not only in terms of some interesting troubleshooting work...but also the great insight and learning curve that comes from knowing more about your engine, particularly the electrical/ignition side of things.
Always comes in handy at some point.....often in helping someone else out of a similar situation.

All good
Coley