Regarding connectors, when I first wired up my first dyno powered light, it was a B&M light and it used the 2.8mm spade connectors. So, I bought more of the 2.8m spade connectors, both male and female, that is what I use for all my dyno powered connectors wherever I want to put in any quick connectors.
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In the photos below I have the headlight on my rando bike. The mounting bracket is the extra long one, I bent it straighter to raise the light up higher so that the fender causes less shadow. And yes, it is mounted off to one side being on my right side canti brake mount, but I see no problem with that, it works fine. My fork crown area is already pretty busy because I am using a canti brake hanger on the fork crown. I used some M6 threaded rod to mount the light bracket to the canti brake post to make sure I had adequate threads in the post, used blue loctite on all of the fittings to make sure nothing comes loose. It is after all part of the brakes so I really do not want anything to come loose.
The Sinewave Revolution is zip tied to my handlebar bag bracket, that is a USB charger powered from the dynohub. The way this is wired, I can add or remove the Sinewave from the light wiring, it is wired in parallel. When the light is on, minimal power goes to the USB charger, turning off the light puts full power to the charger. And I also have a taillight wired into the system, but the taillight wiring is temporary so I am not showing that.
Wires from the hub are black, zip tied to the fork blade with 2.8mm connectors at the fork crown.
The wiring is a bit busy because I also have a wired computer on the bike, the wire that is wrapped around the canti cable hanger is the computer wire.
I have plenty of clearance between my handlebar bag and the light, more than I need.
The bikes with internal wiring look pretty nice, but quite frankly I do not mind having external wiring. I have no desire to get out an electric drill and start working on the frame.