I did an experment last night taking my WBBB, with a Shenandoah (40F) UQ from JRB and a Eureka Hoback (60F) sleeping bag http://www.cabelas.com/p-0043264517614a.shtml , down to 50F. I'm a warm sleeper so I did the experiment in shorts and a t-shirt to make my experiment broader for others to use my info for themselves. I slept 4 hours sraight with no problems then the foot box somehow got out of the UQ and I awoke because of cold feet. I used a bungee cord (I'll replace it with much lighter shock cord for field use) to hold the UQ higher up on the hammock. I also put on some socks and a knit cap and slept well until morning waking up alittle chilled but not cold. Conclusion; The system worked well down to 50F, next time I will wear my polypro-long johns,wool socks, a knit cap,and possibly a fleece shirt, the whole night.
I have taken my WBBB double layer down to 40F with a Therm-a-rest pad and using the Shenandoah as a TQ and I was quit warm all night. Does any one know how cold someone could go down, temp wise, comfortably with a pad, a Shenandoah UQ and a 20F sleeping bag as a TQ? Has anyone ever used a GI poncho with a liner in it, as an under cover, to trap some of the heat that will escape from the sewn through part of the Shenandoah UQ, with success? Please let me know.