Folks vary in their results with VBs/space blankets. As condensation occurs when air with vapor in it contacts a cold surface, below the dew point of that air/vapor, I always have trouble understanding how folks get condensation on a warm space blanket. One which is between the person and all of their insulation, and should be very close to the temperature of their back. Not saying it does not happen for numerous folks, just saying it is hard to understand why. As opposed to condensation on the cold surface of the UQP- it is very easy to understand condensation there, as it is in fact to be fully expected. Although, a slight amount of condensation will occur inside "sealed up" VB socks even when inside socks or boots. But it only occurs to a certain small amount, enough to feel damp. Or I suppose it is condensation, at least it feels damp. But this may just be vapor not being able to escape the closed up socks. Apparently, once 100% humidity is reached, the body stops producing vapor. Unless of course you over heat and sweat.
Condensation can occur even on a breathable surface, or in the outer layers of cold insulation.
Also hard to understand is how some folks get condensation on the insulation(cold) side of a VB. Considering that they are waterproof and NOT breathable, with no claims to be like GTX or eVent. But people do report this. How does the vapor get across the VB so that it can condense on the cold side? I don't know. Do you suppose it is possible that some space blankets, even if supposedly waterproof, are actually breathable? Who knows.
Anyway, I am so far one of the lucky ones. I have used a space blanket ( and apparently it is also a VB) with my HHSS and inside my PeaPod on and off for years now. So far, I have never had anything worse than a few drops of moisture water laying on top of my space blanket, and even that did not get my clothes damp enough to notice. And I'm betting even that was sweat, not condensation. Mostly absolutely no noticeable moisture. Only significantly increased warmth and very dry insulation. It's good to be among the lucky in one thing at least!
A $3 WM space blanket from WM could tell you a lot quick in a back yard test. You should try it. Who knows, you might be one of the lucky ones too! And it is a lot cheaper than a new breathable UQP.
Just make sure everything under your hammock is covered as much as possible. A problem might be your leg area on the foot end away from your short torso UQ, because there is nothing to hold the SB up snug against you legs/feet. The UQ should hold it against your back and keep it warm, but under your legs? Probably not without some kind of mod. So you might get some condensation if the sb is too far from you to keep warm. But still, it should keep the moisture off of your UQ, and any condensation should be on the sb down in your UQP away from your hammock. Unless the UQ protector fits snug against your legs. But you could cut it or fold it just over the UQ I suppose.
What about those snap on reflectors Brandon used to offer for the Yetis? Were they breathable? Did anyone ever use those, if so any condensation?
EDIT: just found this thread re: WB snap on radiant insert(discontinued)