At -20C, you wont really need gloves whem loading ig ypur circulation is OK.
Its pretty dry at that temp, and l often work for a good while without gloves, with no bother.
Im with SvottC, and wear a loading block around my neck inside my shirt.
I just use deer tallow, buf it usually slides down the bore alright.
Flat patches sometimes need holding in the mouth before loading.
Remember minus 20C is only half cold!
We have had a fair bit of this already, and am still wearing my flat cap.
It feels warmer than minus 5 does very often, as the air is drier.
Best,
R.