I’ve bastardised one of those out-front, under slung Go-Pro mounts (like robbo1234biking posted above) onto a Stem top cap (originally a Garmin mount cap) on my rigid MTB, the mounting screws happened to be on the exact same size and pitch.
So now I’ve got my BH1000 (basically the same mounting features as the 1600) mounted bang in the centre over the stem, it’s great (IMO).
I’ve also got one of those out-front mounts on my Road bike so I can put the same light on there, but TBH if I’m road riding at night I’ll use my winter road bike with Dynamo lights and a basic USB charging mini LED light, Full owl melting capability on the bars is really more use offroad.
Oh and I’ve got a cheapy 31.8mm Go-Pro mount with a split clamp like this:
IIRC it was like £2 and a month or so wait from China, but it’s come in handy a few times for mounting lights both above and below bars on a few different bikes, worth having just as a fall back option.
But yeah Go Pro mounts are definitely the best way to fit lights to bikes I reckon.