This way is the most efficient of producing a second coil meant for a headlight or accessory.
Quite a bit more efficient then bridging your magneto with an external bolt on one.
I might have to check the newer coil's, slightly thinner wire will produce higher voltages while keeping the resistance the same which both are critical for these ignition types. Not jumble wiring the coil will also do 20-40% more. I still have and run my ancient old magneto from a 09 motor.
It won't if it's done proper. I have a chrome headlamp that's been modified with a COB LED that I plan to run with a custom bridge rectifier/regulator on a new build in the works.