Do it. And what's one jacket more or less?I am going to LL Bean to check out their thermal henleys that have some wool component. The idea is to have only one layer under a leather jacket in weather down to 32F. Of course the jacket will have a quilted warm lining; we'll see if one layer underneath is enough. Most of my jackets are pretty close fitting and wearing a sweater underneath constricts movement in shoulders and make me feel like a sausage in a casing. It has been a constant struggle for me to solve this for winter time. I think the solution might be a 5* B-2 (or a @MrProper special) and a t-shirt, lol. But that would mean yet another jacket...
But I also have a few vests that I like to wear under my jackets. They are quite thin, but warm well. And some knitted vests.