I don't think they can tell us how much load the blue wire / switched hot circuit in a pre 70 a-body can handle. They do know that attaching at the coil or the wrong side of ballast resistor would result in less than 12 volts to their choke ( due to the ballast resistor ), whether the choke robs voltage from other circuits or not.
I just asked them if the choke shuts off when open. If we can have a conversation I will ask what current the coil heater draws.Yes, they won''t be able to tell us what our circuits can handle. The ballast wire could control a relay though.