The small pack crowd must be using less bulky sleeping arrangment and know more tricks than I . . .
Ideas, some better than others:
* Expect/know how to shiver/suffer, if you go too light or screw up. The safety margin may be narrower.
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* Make all insulation work for you. With a 25F synthetic sleeping bag, a warm puffy, a hat and more, you can go below 25F. Bring spare warmth. Dry gear is precious.
* Stay dry. Stay warm. Hydrate. Eat. Stay active.
* Extra fuel. Reliable stove.
* Hot water bottles at night.
* Sleeping pads are imperative. Bulky foam pad often rides outside the pack.
* Be willing to go home. Work up to committed objectives.
* Unmanageable weather is bad.
* Packing order matters.
* Heavier and warmer can be better. Climbing is anarchy; do what feels right!
Personally, the charm of a small pack is the required attention to essentials. I've jammed everything for a summer trip into an 18L pack, then emptied it into a 60L. Lightweight nirvana, roomy pack.
A compact pack isn't inherently light. 30L of water weighs 66 lbs. If required, a lot of stuff fits in a tiny pack.
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In terms of pack choice, some ~"45L" packs expand to 60L.
(i don't like the thought of fishing through a huge tube to find the probe at the bottom).
I put the probe in the backpad sleeve. It doubles as a pseudo-frame, and is easy to find. After a couple years, the sleeve bottom tore, but it worked until the pack wore out. Keeping pack contents dry after shoveling is harder (just switched to a closed-end shovel to help fix that).
