I downloaded the 1972 manual from MyMopar since they don't have a 73. That is what I have been using. I opened the two page electrical in MS Paint and as I add a circuit in my drawing I erase it in the book print. I have been using the pages you mentioned. They have helped alot in better understanding the prints.
I kind of figured about the junction but wanted to verify. Lots of that going on. Feels sloppy to me. I like dedicated circuits.