I see a lot of thought and effort going into this, so how about one small suggestion for keeping it from corroding like the other parts have done in the past?
Industry often uses a dielectric grease on connections that they want to last. Perhaps a product like No-Ox-Id?
We find it is good to warm it slightly before use as a way to make it much easier to paint on in a thin layer as we put things together. Some of the ways we heat it are laying it on the truck engine if you have been driving or a trouble light works fairly fast as well. Hot water can do it but gets spilled too easy if taken around the batteries!
But if you paint it on the parts like a bolt and then as you add each connection, you can get a thin layer that will "glue" itself together and as it cools and sets, you can get what looks almost like plastic formed over and around the connection. That super thin layer will then seal all the air, water, etc. out but be easy to remove the parts when needed in any future work. Avoid wiping with a rag to make holes in the layeras it stays soft!
Even at $7 a tin, it saves enough do-overs to be worth lots more!