Asbell wool is absolutely part of a layering system for the deep cold. We wear them alone in early season, but later on (like now) I start with a windblocker vest, and then add a Asbell Sherpa vest on bitter days, or just a plain wool vest. Maybe throw a wool shirt or sweater (I have had a Filson sweater for years, I use the heck out of it in layering)and a zippered jacket over that.
I love that Teresa now has Zippered Jackets instead of just pullovers, it makes the layering SO much easier. I choose whichever plaid pattern fits the terrain.....usually Evening Stand Green or Brown for ground hunting, and Timber Ghost for treestand sitting. Because of the layering, I don't consider what weight they are at all.
An alternate to what I just described, is to have one base Asbell garment....such as the Anorak in grey or green, and use the vest's in different patterns for both layering and camo effect.