Note 1: 2-wire and 3-wire alternators seem to be identical, the only difference being how many brown wires are connected to the plug and hence the alt. Where two brown wires are used, one thick and one thin, the thin wire is a voltage sensing wire. Later models had two thick wires, these are both output wires for a higher current carrying capacity.
Note 2: V8s used the 1971-72 system i.e. a single thick brown. This is connected to a stud under the RH toe-board together with the thick brown from the ignition switch etc., not to the starter solenoid.
Note 3: On North American spec 1976 models (no ignition relay) there are two thick browns from the alternator to the solenoid, and from the solenoid to a white connector block by the fusebox (shown below, arrowed), to increase current carrying capacity. From here one brown feeds the fusebox and ignition switch, the other the main lighting switch. A third brown from the solenoid feeds the starter relay and hazard flasher fuse.