It can be confusing when talking about technical areas vs car model areas, but we do have the "Ignition and Electrical" sub-forum here: https://forums.hybridz.org/forum/16-ignition-and-electrical/.
Yes, I think it's fairly common to add new circuits/etc to these old cars. I've done it to the last couple of my cars to simplify/improve the electrical capabilities over the stock harness. I've always used off-the-shelf breakers, relays, fuse panels, switches; but there are a bunch of pre-built kits that are available through numerous vendors. I like to use marine hardware if I can find it; as it's typically extra beefy and durable.
Good luck with it; and please be sure to post your results once completed!!