[blucar]

You did not mention in your write up if you were referring to original reflector type lights or sealed beams.
The reflector '39 and earlier lights are a real pain to work with. I converted the headlights on my '36 to sealed beams in 1952 using a conversion for truck lights and '36 trk bezels. My lights don't have the '36 "bug eyed" look, but they work great.
I got rid of the original switch on the bottom of the steering gears in favor of a dash mounted pull switch and a floor mounted dimmer. I also wired in a relay in lieu of direct wiring, the relay cut down voltage draw and made the 6v lights very bright.
I have driven my car for thousands of miles over rural highways in all kinds of weather.
I have a '39 conv that I converted over to halogen head lights, big mistake, the halogen bulbs don't work with the prism's in the lens, lots of un-directed light. I am in the process of converting the '39 back to bulbs, having reflectors nickle plated, securing new sockets and using Ron Francis 'Bright Bulbs.