Long ago I went to using as warm glove as needed on foreend hand, as well as leather hand/barrel guard on guns with no "wraparound" foreend. On trigger hand I use whatever glove lets me get finger into triggers easily and, if needed, keep that hand in warm pocket on coat or shooting vest.
I also only shoot "northern" doubles in cold weather. That is, doubles that have ample space between front and back triggers and between front trigger and front of triggar guard. One could, I suppose, use guns with only one trigger.
Niklas
