Definitely mittens, not gloves, except for a quick drying liner glove inside a mitten.

I bought some Dachstein mittens recently; these aren't light, but they're dense wool and very warm. Too warm for most situations; I tend to use OR PL 400 mitts in most situations instead, but when it's really cold (or you're really cold) Dachsteins are perhaps the best you can get for warmth. Though if you could get some made from your Alpaca post namesake, those would likely be very good too, maybe look for mittens from Peru ... :-).

Add a mitten shell for the weather resistance factor you mentioned and give up on the idea of dexterity while wearing the mittens. That's what the liner gloves are for. Remove the mittens temporarily to do "fiddling with hands" tasks, and do those as little as possible. Keep mittens on your hands most of the time and that should help a lot.