Three wire alternator on a two wire system?

If I understand this correctly, here is my plan (correct me if I'm wrong).

With the alternator that I have, I should buy a 70+ voltage regulator. Something that looks like this:



Then I can get a pigtail for it that looks like this:



The blue wire would splice into my existing blue wire at the current voltage regulator and the green wire would be a new wire that would run to the alternator.

If that is all correct, my only unclear area is the second wire that is connected to the current voltage regulator (u-shaped connector held down by a screw). What happens with that wire?