Okay, I am starting to like the one low, one high approach.

I am currently running a Radbot 1000 (set on flash) on my rear rack and a DangerZone (steady) on my seatpost. Not a lot of vertical separation, but the one solid, one blinky is a great combo for getting noticed and giving reference location.

Is there a good helmet-mount product I could add to the mix (preferably one that runs on rechargeable batteries)? I suppose I could move the DZ up higher, but I'm not sure how I would attach it to anything confidently.

I do like the look of the topfire and fire eyes linked to earlier; might have to check one of them out.