I will try and keep this short, and the least technical. The heat exchanger is your regulator. I need to point something out, reducing the headlight load and city lights to LED would amount to about 40 to 50 watt reduction. That 40 to 50 watts will end up going to the shunt regulator, I don't know if the design by the manufacturer allowed for the additional heat, and I doubt most members on this forum understand how a shunt regulator works. Imagine having a generator at home and running some loads in your house during a power outage off the generator,the voltage regulation would be done by adding loads to keep the voltage at a proper level ( the shunt regulator adds load in the form of wasting energy to ground as heat to keep the voltage from exceeding 15 VDC ) every time your fridge would run you would need to unplug the equivalent load, every time it stopped you would need to add the equivalent load to keep your light bulbs from blowing. Stopping there, for those technical, the generator comparison I have ignored frequency .
Comments earlier about paying someone to install a series regulator seemed ridiculous, I would expect to pay $121 GBP which would be the cost of a used polaris 4012941 and the labour to install it. If you know how to solder, or are well versed in proper crimping, I have photos on wiring , recommend the Triumph harness for about $6 GBP , I would say my wife could do the wiring, the challenge for her would be getting the gas tank off and getting the bike strapped down on my lift. Due to the fact I have spent several years refining this, and the fact this forum caused a bit of grief, ( not saying I wasn't partially at fault) I will not post anything related to series regulators on this forum, as to photos or how to proceed.
Those who wish to proceed to convert to a series regulator can PM me, all my technical posts are copyright protected on another forum, only accessible to members.