I don't know where you got your voltage regulators from, but I went through 3 of them from CarQuest back in the day, everyone of them junk. Either high, low or inconsistent. I went through the alternator, all my connections, and when it came down to it, it was always the regulator that was jacked up.
Now, with the 280ZXT alternator, the output is stable, makes enough juice at idle to keep the battery charged with accessories and lights on, doesn't kill the battery when driving stop and go on a rainy day with A/C, heater, defroster, lights and wipers on... so much nicer.