As for most of us weight is not a problem (i.e. being ebike riders) I'd go for a system like MagicShine. Very bright even in daylight, either on full-beam, dip or strobe. I have a white one on my handlebars, and a red version mounted to the back of my helmet (runs off the same battery pack).
The battery pack is mounted on the crossbar, which means leads running in both directions, but again, as ebike riders we're used to wires!
There are Youtube videos of the MJ818 showing just how bright it is. Expensive (the front light was about £75, the helmet extension another £50) although you could pay a lot more.
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