Baldy,
The schematic is not "wrong" - I just accomplished the same flow of electricty by way of a slightly different routing of wires (to use the existing wiring as much as possible).
Here is what I tried to state (and, this agrees with your statements): Alternator to ammeter; then, ammeter to the starter battery-terminal; then, starter battery terminal to the battery. I also ran a lead from the ammeter to the ignition switch.
The diagram in my earlier post is for a system that has a two leads coming from the battery - one to the starter and one to ammeter. I did not want to buy a new two-lead battery cable (but that would have worked as per the diagram).
Both the diagram and my adaptation have the one wire from the alternator going to the ammeter.
"Alternator to ammeter to starter [battery post]" Thus, the ammeter works and the battery charges, and the starter gets power from the battery.
And, at about 800 rpm the alternator starts charging (800-1200 rpm, depending on the model of one-wire alternator). Once the alternator is "excited" into charging, it will charge at all rpms.
Sorry about my lack of clarity.
Tim