I am restoring a late 1940s Velocette Mac 350 motorbike. I have a few working dynamos for this bike, but the original regulators are hard to find in working condition. I bought a regulator on Aliexpress, but I am pretty sure now that this regulator is designed for an AC input (Alternator), rater than the DC output of a dynamo. Back to square one. I intend to use Led lights, but the original horn is a 6V one, so if possible I want to regulate the dynamo output to 6V DC, it will produce higher voltages depending on RPM, but I'd like to keep the output voltage to a standard 6V if possible. I was going to use 2 x ultra capacitors on the output of the dynamo instead of a battery, because even I will be losing some capacitance having by the caps in parallel I think the caps will soak up any slight variations in the power output from the dynamo and provide adequate lighting for a while when the bike is stopped. This brings me to my question, but feel free to pick holes in my idea if you think it won't work, I was thinking that instead of the standard regulator, I would use a buck / boost converter to keep the voltage around 6V. The Leds will accept from 5v to 30v so it's really only the horn that I'm worried about.
Edit: This is a Miller type DVR dynamo, that is regulated by default by varying the voltage in the field winding. It has no permanent magnets and outputs a DC voltage.