[Alfajay]

...there is the "W" terminal which I think is a tachometer connection for a diesel engined vehicle.

Yes, that makes sense. A google search of "alternator terminal W" turns up:
The W terminal generally outputs an unrectified AC voltage, the frequency of which is proportional to the engine speed.

But that doesn't answer where the warning light (the green wire) goes. It does seem odd that the alternator came with the radio suppression capacitor connected to the D+ terminal, since D+ serves to excite the alternator by delivering some power when the ignition is first turned on. Obviously the suppression capacitor doesn't provide that function.

A google search of "where to install alternator noise suppression capacitor" turns up:
The capacitor positive lead goes to the alternator B+ terminal and the negative lead goes to ground on the alternator.

One question is what that smaller stud is for - one one with the white nylon insulator at 12:00 in your picture. Is that also B+ and the capacitor should go there instead? Or is that also D+, and the green wire can go there? But either way, why is the capacitor plugged onto the D+ terminal if it typically goes to B+? These might be questions for Classic Alfa.

 

[Alfajay]

it would seem that all I need to do is crimp a ring terminal on the capacitor lead and connect it to "B+". With the green wire going to "D+" and the red positive going to "B+" this copies the original alternator connections.

Yes, that makes sense.