RE: is under armor anough
I'd go with UA, with a pair of sweatpants, then my camo pants.
On top, the UA shirt may be enough, if you have a really heavy coat. If your coat is thinner, a sweatshirt should do it.
All bow season, I got by wearing only the UA (cold gear)top & bottom, my fleece jacket,my camo pants, a pair of UA heavy Armourblock moisture-wicking socks, and my Alpha Burlys.
If the temps are sub-30, I'd advise adding just a layer of sweats. If you're anything like me, your toes will be the first to get cold anyway.