Thanks for taking things in stride. The title change I'm sure helps.
The point on semantics is pretty clear, if you search combo switch as per the previous title, it brings up hundreds of links to the headlight combo switch, and a few on the blinker/high beam combo switch which are a very common problem. Switching relay module or mult-function relay per the part number brings up much fewer, but more specified posts, using the part number you get very very specific, but few posts.
If someone else in the future is looking for the same CA specific relay switching module for the blinkers or turn signals it should now pop up and you will potentially be their savior pending the solution. Don't worry you aren't alone, when I announced I had ordered pipe for my tubular control arms, people were quick to correct me or to make sure I was using the right material. In my mind I know I meant tube, DOM A513 to be specific, but coming from fluids and flow I was thinking pipe, slip of the fingers and now I had to sit and try to convince people I wasn't trying to build structural components from used rusty drainage pipe.
I think it is clear now that you are looking for the CA specific switching relay module/multi function relay, or a work around for that. In the early cars the lack of relays did send a lot of amperage through not so great connections, so I would suggest maintaining a relay point rather than a direct wire unless you are using low amperage items like LED turn signals. Pin it out and swap to a modern relay using male spade connectors to a 4 or 5 post 12v automotive relay.
I have to say this forum was such a place, at least 9 years ago when I joined. My first posts I was dinged for grammar/capitalization. However, that is part of the character of this forum. You get a specified knowledge base that is immense, in return you may have to do a once over on your post and try and use the common term. So I will say don't throw the whole forum or forums in general under the bus. Keep in mind we could not be here if it wasn't for the generosity of donations and the hard work of those on the network end. We almost saw closure a couple years ago and then you would be relegated to searching through facebook posts.
We are more oriented around engine swaps, suspension tech, and such. Looking for stock replacement parts, you may have an easier time on classiczcar as they are excellent at finding and maintaining the stock Z platform and will most likely have found a more bolt in/plug in solution if you are not familiar with pinning out relay wiring. You might try datsun parts and needs as there are a lot of Californian members, ratsun as well who may be able to find you a used replacement part.