[deuce_roadster]

Welcome! You have already got a lot of good advice from a very experienced member of this forum. I would add that if you can find NOS cables and lube them you will eliminate the possibility of frayed wires inside the sheath they reside in which can prevent the brakes from releasing. I have seen that happen on 37 cars and I would think the 38 cables would be similar. A spare stock coil rebuilt by Skip Haney would be a good thing to install if it hasn't already been rebuilt. You don't need 12 volts when everything is the way it is supposed to be.
Good luck and keep asking questions.