How would this combo fare for the coldest sections of the AT during a Thru hike? Also for those of you who have tried Winter Yeti's + TQ's let me know how low you have gone, and if you think it would work for a thru hike.

I like this combo for a few reasons: Winter yeti is light, as is rocky or similar, and if it works for the coldest areas of the AT, then its what im looking for.