So I believe I've found a problem. I believe that the coil positive is supposed to come closer to battery voltage when key is in run. Instead it goes from near 7 volts with key on and then to near .5 volts in run. Definitely doesn't seam right...
In start, the battery shouldn't drop below 9.5 Volts. This is measured at the battery.
The voltage difference between the battery positive and the coil positive in start should be pretty small. Off the top of my head, a half volt. You can check this two ways.
1. Measure the voltage across the battery with voltmeter while starting. Then repeat or at the same time measure voltage at the coil. Subtracting will indicate voltage drop in the wiring and ground.
2. Measure the voltage across the battery while starting. Then measure voltage between the battery positive and the coil positive while starting. That will show voltage drop in the wiring.
Voltage across the battery during starting shows the condition of the battery.
Voltage drop in the circuit indicates resistance to the amount of current flowing.