No, needs full +12v. connect to the ignition 1 circuit of the engine harness, typically blue wires, opposite side of the ballast resistor from the coil feed.
Don't hook it to the coil, it'll lower the voltage too much. I think the instructions even say that. As has been said, the full 12 volt side of the ballast is fine.
On a '69? Shouldn't have a blue field wire.splice into the blue wire going to the alternator.
There is no set left or right on a factory configuration, what color wires are connected to your Ballast? Normally dark blue is the ignition 1 side and brown is the coil side. Could always check with a VOM, disconnect one lead, turn the key on, check where the voltage is.
splice into the blue wire going to the alternator.
On a '69? Shouldn't have a blue field wire.
Dark blue going to the REGULATOR.