So...newb question on the subject.
From a clothing perspective, you wear different layers to accomplish different things to keep yourself warm in a cold environment.
Closest to your skin is a wicking layer, like UnderArmour. The intent is to pull the moisture away from your skin, preventing cooling and/or overheating.
Next are insulation layers...often wool that has good insulative properties even if wet.
Then the outside layer is the vapor/wind breaking barrier. It prevents moisture from reaching the insulative layers, and prevents the wind from pulling warm air from them as well.
Why wouldn't you layer in the same fashion in a hammock?
Seems to me that you'd want to have some kind of wicking agent if possible closest to your body...then your insulation layer(s), and on the farthest outside your vapor barrier. So I'd assume that your vapor barrier/windbreak would be OUTSIDE of your UQ, not between the UQ and hammock.
This is assuming that the vapor you're trying to avoid is coming from outside moisture, not sweat. Sweating would be avoided by temperature regulation inside the hammock/sleeping bag/TQ and clothing, I'd think.
Again...I'm a newb...asking a newb question.
Where am I wrong, and why? Thanks!