I got a MMG single layer Sock without SEEP for my WBBB over the winter to extend my 3-Season CrowsNest into colder temps. It work great, I was even able to lay a poncho liner in it, loose, under the UQ, and that really warmed it up. It helped me keep warm down to 14* at the NJ Winter Hang. But, to my surprise, I've started using it more and more in the warmer weather to

In fact, I tend to think of this more as an UQ than a sock, an UQ that can be added to my down UQ to supplement. And, with only the 3/4 UQ and IX sock, I don't need a foot pad. When it's warmer, I'm good with just the single layer sock, no other UQ, down to about 55*. It's like a having a lightly insulated shell jacket around my whole hammock. It's like an IX version of the Speer Snugfit.

It's light, at about 12 oz., and stuffs into the same size sack as my CrowsNest came in. As a bonus, it also makes a supper comfy pillow in the stuff sack when not in use.

To sum it up:
MMG IX Sock without SEEP (w/ CrowsNest Pillow) = Summer Kit
3-Season CrowsNest (w/ MMG Sock Pillow) = Spring/Fall Kit
MMG IX Sock without SEEP + 3-Season CrowsNest = Winter Kit

Here is my setup with the MMG IX Sock without SEEP at the 2011 Spring MAHHA. As you can see it goes right up to the zipper on one side and just under the shelf on the other.