After all the years of Pennsylvania winters I use a wool split palm mitten and lined leather or wool gloves under, but I insert a hand warmer pack in the front of the mitten near my finger tips
The warmers for the toe have sticky strips that hold them in place in the mitten. When using this set up I can use a glove with an exposed trigger finger without getting cold. This is what I wore in the minus 9 degree`s hunting the boar.... No problem`s. When the heat pack gets cold I shake up another and are good to go.
PS the same as 7P above...