I added the negative buss bar, a terminal strip, and moved the connections for the Echo Charge from the battery terminals to the back of the battery selector switch (because I don't like stuff connected at the battery). Not shown here are the connections to the battery charger, which is also connected to the back of the selector switch.
Regarding the wiring diagram, while I believe that this is a good idea, and I recall seeing one for a 1985+ Pearson 30-something, I also think that it may be impractical.
Realize that wires are located in three dimensional space. A diagram only represents the location in two dimensions. How would you discern a wire running through the headliner from one running under the cabin soule? I guess that you could construct several diagrams showing "layers."