I haven’t tried to measure the Vf, but the data I found suggested it should be about 2.3V at 700mA.
Sorry for the delays… I still haven’t assembled the other two hosts so I don’t have pics yet or final firmware. I did fix my firmware flashing hardware though, so hopefully it’ll be easier to reflash now. And I got a chance to try it on the road… I don’t remember now whether I was using the first or second flasher (first, I think), but from about a third of a mile away it was about as visible as a car tail light… with plenty of room to get brighter if necessary.