Thanks 2M. If you don't know enough about it... Sounds quite possible, though. And I'm less worried about the voltage swing after seeing it bounce back a few times.
Here's what I've observed on my commute home, the long way.
Still no lights, cruising voltage dropped to 14.0v after a half mile or so. This stayed consistent for the next 8 or so miles. At this point, dusk was beginning to settle and I put in the lighting fuse.
Now, with the lights circuit inline, cruising voltage was a consistent 13.7/13.8v. Not too bad.
Here's a concern: sitting at idle with my lights on, voltage dropped to 12.0/12.1v (12.5-12.7 w/o lights). As I took off, voltage would jump up to about 12.7v, then slowly raise to 13.8v. Not good for riding in city traffic. I'm going to guess this is a symptom of a tired battery?
All told, this rectifier has seen four heat cycles, 30 miles without lights, 10 miles with lights. At the end of today's ride the rectifier was cool to the touch and diode numbers were up where they should be, .
Still Hesitantly Optimistic in Phoenix
One more thing I observed this evening, AZ Bike Week is obviously here. The streets are packed. Mostly groups of 10+ on custom machines that strangely look very much alike.