I went to bed about midnight when the temp was 40. Lowest it got to was 38 about 3 am. I started with just my typical cold weather tent camping clothing (polypro longjohns, top and bottom, polyster hooded sweatshirt, and a fleece, wool blend socks) and a blue 20" walmart pad.) I zipped up the weather shield and tucked the bug net into a mesh bag to get it out of the way.
After about an hour the sides of the hammock were chilly, so I decided to try my frog sac equivalent that I made from a $20 KMart sleepcell Cellcorp sleeping bag rated at 42 degrees. I fell asleep shortly after and did not wake until 3 am because of a need to change sleeping position. The sleeping bag gave me suffcient insulation on the sides of the hammock.
When I woke at 3 am the temp was 38. I noticed that the weathershield on the side to which my head was turned had stated to collect condensation from my breathing on it so I unsipped it on both sides just far enough to have it fall away from my head and lay on top of me.
I was very comfortable except for the slight chill on my exposed face, which I can probably eliminate with a balaclava or bank robber ski mask.
If the walmart pad had been 40 inches and had curled up around my shoulders and side, I might not have needed the sleping bag, or may have only needed a bag on top me in quilt like fashion. The part of my body on the walmart pad was always warm.
I will probably try my homemade spe or mayber an insultmat tonight - unless I can get my hands on a rental BA insulated air pad from EMS for testing (I have two being shipped but they won't be here until wed and I'm leaving for my backpacking trip on Friday and won't have a chance to test them.)