I bought a Transpo voltage regulator at a local small engine repair place...actually I think it was a Bosch repair place. Transpo makes both an adjustable and non-adjustable type (IB301). I bought the latter.
I have a unusual situation...heck it might be more common than I think. I have the Lufty fairing with clock and voltmeter. I ran power to all these and collected their grounds to a common lug in the left fairing pocket, then ran one ground wire out to the coil mount bolt. My voltmeter is wired directly to the battery. It was always seeing 13.5-13.8v...never higher. Then one day, I took the ground lug apart, cleaned the entire connection, used some good washers, and coated everything with a dielectric grease. Bam! Voltage now showing at 14.1v.
My experience is with the /5 and /6. If you don't have actual voltage of more than 14, you are headed for trouble. Of course with modern technology and inflation, it could be different today.
I have witnessed that many don't know how to measure the charge voltage accurately.
Ask the Indians what happens when you don't control immigration.