I'm a veteran backpacker who has not yet been in a hammock, but I like everything I've been reading about hanging. I sleep almost exclusively on my back but switch to my side when my lower back stiffens up, as it inevitabley does when sleeping on the ground. I'm seriously considering investing in a WBBB with underquilt, but first want to test whether I can sleep comfortably in a hammock without making a major investment. I have quality gear for tent camping, including an Exped 9 Downmat sleeping pad (not the wide deluxe model).

REI has a good return policy and sells Hennessy hammocks, so that would be the most practical choice for my initial test. I'm considering two hammocks: the Expedition Asym Classic (bottom entry) and the Expedition Asym Zip (side entry). I'll be camping in cool temps (maybe down to 30) and don't have an underquilt, so I'm wondering whether my Exped Downmat 9 would provide enough under-insulation inside the hammock, and which of the two Hennessy's mentioned above would work better with it or if an Exped 9 is doable in a hammock at all (I usually don't inflate it all the way). I would think the side entry would be better for getting on top of a thick inflatable in a hammock, but I have no experience with this. Top insulation would be my opened-up Western Mountaineering Ultralight 20* bag.

I'm heading to the mountains of North Carolina in a week with a buddy, and he'll carry a lightweight 2-man tent (Lunar Duo) that we can share if the hammock & pad combo don't work.

Any advice?