I've 'not slept' in -3 with the Hunka and a down jacket but I wasn't actually tired so it's hard to know if it was just the cold the kept me awake or not being all that sleepy.
I think a bivvy that fully closes would help since I'd be recirculating warm air and could open the top when it had warmed up. The drawstring closures don't cover my face enough when closed up.
Maybe a slightly bigger one too which doesn't stretch tight against me.
I've 'not slept' in -3 with the Hunka and a down jacket but I wasn't actually tired so it's hard to know if it was just the cold the kept me awake or not being all that sleepy.
I think a bivvy that fully closes would help since I'd be recirculating warm air and could open the top when it had warmed up. The drawstring closures don't cover my face enough when closed up.
Maybe a slightly bigger one too which doesn't stretch tight against me.