I think if there'd been somewhere to actually lie down (as there will be on the 600) I'd have managed Actual Sleep for 45min or an hr. I suspect I'll be working on similar timings for the 600 so it will be pretty tough... Oh well, see what happens :-)

Dynamo-driven (Schmidt hub). I like fit-&-forget; although I do run batteries on the rear as they last so much longer than front lights & don't require as much in the battery line anyway.