First experience was not a smashing success or total failure - just need to tweak my system and inspect the setup. Last night, temp got to 31 with windchill down to 25F.
First lesson learned: As the wind picked up, it was obvious I did not have the tarp edges as low to the ground as they should have been to effectively block the wind. A 2:00 AM re-staking was real cold. I'll check that next time before climbing in the hammock.
I was never "warm" - not freezing, but not comfortable warm either. I really want to inspect my setup closer in the daylight today (I set it up in the dark last night) to make sure I have a good fit on the UC, pad, and SB. I used a reinforced SB like this one: http://www.cabelas.com/product/Sport...h-All+Products
I wonder if I would get better heat reflection from one of the thinner mylar space blankets? ...might try that tonight. I'm also considering inserting a synthetic sleeping bag in the UC - not sure if underneath the pad or between the SB and the pad is best?
The 40F top quilt (Sierra Stealth) actually performed well - as long as I kept it cinched around me tightly. Not sure the silk travel sheet added much - trying to use it in the hammock with a top quilt was a bit of a wrestling match. I wore upper and lower underlayers with a fleece upper pullover + wool socks.
I hate to change too many variables while I'm trying to get a baseline setup and temperature synchronized, but unless I find a setup problem, I suspect my current gear may be a bit taxed at subfreezing temperatures - as BillyBob has confirmed with his experience.
One final observation: I may have my foot end a little too high (read many tips to raise it several inches above head end), but how far into the hammock are you laying your head? I seemed to be searching for the sweetspot where my 6'-4" frame could lie level without feet above head or vice versa.
I plan to make some adjustments and try again tonight... thanks for all the experience and tips shared on this forum. I watched so many setup/rigging videos before my hammock arrived that I feel like I've already set it up 1,000 times.