>>811903When you lay on something, it compresses the insulation. Any soft insulation needs loft to keep you warm. Your body flattens it. Pads are fine in the hammock as they are specifically made to be laid on.
It's especially bad with something made with down insulation. Down compresses really well which is great in your pack, but when you're laying on it, it's essentially useless. Couple this with the fact that there is always air moving under a hammock and you get cold fast.
The woobie under the hammock keeps it from compressing, maintaining the loft and insulation properties. Inside the hammock it would retain a little insulation quality, but you'd be amazed how cold you'll get in a hammock.
Don't worry about wanting the soft woobie to lay on, that's what the hammock is for. Your can also use another woobie for your top insulation if you want, so you'll have a woobie hanging below the hammock, and a soft woobie on top of you. Double your woobie double the fun.
>>811894An underquilt is the gold standard for hammock insulation. Unlike a pad they don't move around, and are much more comfortable. You can roll off a pad, and if you move a lot it's always bunching up. They work, but they aren't ideal. An underquilt is used by nearly every serious hammock user.
As for size and weight, an inflatable pad is always always smaller since you can deflate it, but a good down underquilt will compress a lot and be smaller than you'd expect.
Put it this way, a good top quilt and underquilt should pack and compress the same as one single sleeping bag.
