I learned (or maybe re-learned?) this one a couple of nights ago:
Do not – especially in the winter – try more than one new technique or piece of gear at a time!
I made the mistake of trying out a new groundsheet (polycryo vs the Tyvek one I was using) and a new sleep pad combo (Neoair Xlite torso + Ridgerest Solite CCF + pack under my legs). I also did not bring my ~2-foot x3-foot CCF sit pad/doggie pad, thinking that we could both use the Solite pad for sitting, and that his Noble Camper doggie sleep bag would be adequate insulation for him.
WRONG on all counts! I slid all over the place with the polycryo on snow, the Solite and the Neoair were impossible to keep together as a unit, my pack slid out from under my legs and compromised heat retention and the dog got cold without his CCF pad under his doggie sleep bag, so he was constantly worming his way into my bag. On top of that, my inflatable pillow sprung a leak and was useless. Neither of us got much sleep despite nearly 12 hours in the tent.
Too many new variables can make for a miserable night.
The only positive takeaway is that the Solite/Neoair/pack combo works very well down to 0F if they can just be kept together.
Edit to add "doggie pad"