I slept out last night with a hammock for the very first time in my life, I suppose it hit 40 degrees or so. I was using a 20 degree sleeping bag, a space blanket, a wool blanket and a therm-a-rest, with rain pants, a shirt, and a fleece cap. And I wasn't cold, but I wasn't particularly warm either - on the ground, I would have been sweating.
So what do you use to stay warm at 40 degrees? 30 degrees? 20 degrees? What's the coldest you would go down to with a Hammock? At what point to you lower your hammock to near the ground and pack stuff around it?
P.S., Aside from the temperature, it was very comfortable. It did take a little while to get over a feeling of being vulnerable, but that didn't bother me by morning.