I think a fork crown height is best for lights.

I bought a used dynohub wheel for $20, I had a vintage dyno powered headlight in storage, I put the wheel and light on my errand bike. But the light is too low, any road debris (leaves, etc.) create large shadows. Since it is on my errand bike and is only used on well light city streets, it is good enough. So, not going to change it. Light is mounted to the fender mount on the fork with a piece of threaded rod.




But the plus side is that it was the simplest wiring job I have ever done. Both hub and light are grounded to the fork, so only needed one conductor wire.