A while back I made a UQ out of 6oz weight primaloft. I finally got around to testing it today in the cold. The weather channel said it was 32 degrees out with a "feels like" temp of 27F.
Test was great! I had a TQ on made of the same weight primaloft and wore a OR down beanie. I was nice and comfy! I only wore a cotton undershrit (super lightweight), jeans, and athletic socks. Without a doubt, I'd be wearing stuff a bit warmer when I am truly out in the back country and not just testing things out.
So, I am thinking I can easily get 20 or below with the proper clothing on. I feel like I can stuff a down vest or jacket in the area between UQ and the hammock to get additional warmth. Also, a pad can easily be set inside the hammock. With all that insulation and maybe even some warmer clothing, I could easily see getting down to 0.
Oh, I used my 1.6oz weight sil tarp with one end closed off. It made for tight quarters with the doors shut but that really doesn't bother me. Unfortunately the wet snow stuck to the sides but after a good shake it shed the white fluff.