Thanks! I’m wondering what’s going to happen to the unused AC voltage and if my regulator will handle it. Also. If my regulator will overcharge the battery. Only way for me to figure those out will be to ride it and see.
That's why I dialed-down the voltage...to pretty much the same value your system has, in its present configuration. I'm under the impression that these (nominally) 12V batteries will survive with up ~16V. A full-wave rec/rec should dump excess voltage to ground...what I lack is the knowledge to explain how that is accomplished.
Having a voltmeter ought to tell you what's going on with your charging system. Only thing better would be the addition of an ammeter...and that's overkill even by my standards.
I believe that most electrical components are built to withstand substantially higher-than-nominal voltage and most of the half-wave, "balanced" systems exceed nominal voltage huge amounts, that goes for 6v as well as 12v. IDK if it's just the cheap Chinese reg/rec units or the crude setup. When I ran half-wave, with a reg/rec that came with the Z110 motor, there were clear indications that the electrolyte was being boiled-off. I went to a SLA battery a few weeks before I swapped-in the Honda Nice motor, losing the opportunity to investigate further. I mention this because there are also clear indications that the SLA battery is way more tolerant of abuse than the old leakers. I never checked anything but battery voltage, engine not running, which doesn't tell you very much.
Suffice it to say that you've realized a system voltage balance with finesse that would have been the envy of factory engineers, back when these bikes were new models. Between the lack of voltage spikes, over-voltage in general, and the more robust components I see a recipe for longterm success. If that weren't enough, there's a known reg/rec unit available...for less than the dinner tab at Steakback Outhouse...should the worst happen.