Awaiting my Thermoflect blankets, which I expect will show up tomorrow or the next day, I'm thinking ahead to tests to determine advantageous uses for them. I've prepared by getting two other shiny sheets to compare them with - aluminized ripstop from DIYgearsupply and aluminized CTF3 (cuben). I've got a space blanket, too, but I'm more interested in these more durable materials.
I tried the sheet of shiny cuben tied under my insulated hammock once, but had considerable condensation forming between it and the hammock - not too surprising, as the temperature was around 30° F. and the humidity was high. I think I pulled it too close, also.
So, questions: how close or far away should radiant reflectors be from the sources of radiation (us)? What materials will radiant heat pass through easily? (Down, I suspect. How about different synthetic insulations?) How strong, how breathable, how light, how easy peasy freezy, and so forth. Bring on your tests and share your data. One application I want to try is making a wind-break/reflector for winter campfires.