Actually, here are the results of my weekend backyard test...
Top loading hammock, Homemade Climashield XP "multi" quilt as underquilt (w/approx. 1" of loft), JRB Stealth quilt as top quilt, Sock/Pod closed. BlackCat tarp deployed low, but not in full winter mode.
Temps went down to 35F, weather was clear, w/light but persistent wind, most of which was blocked by the Sock/Pod.
Wearing: Polyester hat, 2 Nike Drifit shirts (neither long sleeved), Sport Hill long running pants, no socks.
Expected results? To be comfortable at the 38F temps expected.
Results: I made it through the night, but I'm not sure I could have if I hadn't been in the SockPod and if I hadn't packed a down vest in a pillowcase as a pillow.
I woke up around 1:30am, and found I was pressing the underquilt down with my right foot, resulting in a cold spot, readjusted, went back to sleep. So far so good.
I woke up around 5:00am and was chilly underneath. I checked and re-checked the underquilt to make sure it wasn't being compressed by the sockpod, all things checked out ok. After about a half hour of still being chilled, I pulled out my down vest and put it on. I was still cool underneath (due to compression of the down underneath me), but was able to sleep.
I woke up around 7:00am very chilled (shiver). I was able to stick it out for about a half an hour, but had run out of other options and so I went ahead and got up. I went in the house, the outside thermometer registered 35F.
I could have been warm enough if I had worn more clothing, but if I had not had the sockpod, I would have been back to being cold. It really blocked a good chunk of the wind.
My conclusion: As an underquilt, this quilt's comfort limit is around 38F. More loft or more layers would take it down some.
Next test of the quilt is to repeat the test while using it as a top quilt, which is what I originally intended it for (or as a layering for an underquilt).
I believe this quilt would work fine at lower than 35F as a top quilt. By the way, I was never cold up top with the Stealth quilt, which is rated to around 40F, even with being slightly underdressed.
Hope this helps someone out there...