choke wiring again

Ok i looked again at the alternator and it isn't a 2nd spade like I thought but just a plate that must be grounded to the body like you described. The coil isn't getting all the time 12v from the battery, it is just bypassing the ballast resistor so it gets 12 in start or run. So I will check for voltage loss as you describe but am going to go with the coil + then. If I have too much other loss then I'll shore that up another way. How big of a fuse for the choke?
And yes I have the ignitor II