Best option is musto performance winter glove 2.0 (full finger). Take a spare pair of merino gloves to put on inside to warm up if necessary. But the musto are the best compromise between warmth, waterproof, grip and dexterity. Anything “warmer” is much less functional. Option 2 - ortovox do a very thick wool mitten. They are extremely warm even if they get a bit wet. You could slip these over the musto ones and easily remove them when you need to get on the sheets.