Yes I understand the poor ventilation problem. I was sweating a little last night when I slept with the space blanket. The bivy I bought has a rain fly which can be taken off to reveal a mosquito net top. So, protection from the bugs, a view of the night sky, and ventilation. I think it'll be fine.

I should note the space blanket I got is more of a tarp. It's thick and not the typical crinkly 1oz emergency blanket. Sure it's not quiet, but it's not that loud.

Since this thread is, and I will be on, a light load tour I won't have much gear to bring into the bivy. I'll put the food 50 feet away and shouldn't have much else to bring with me into the bivy. Perhaps I can use the pannier I bring in as a pillow if I keep the clothes on one side of it.

I thought of using a hammock, but decided not to since it would require trees and as you note some places don't allow them. Unless I spent a few hundred on a hennessy hammock I would need to bring a tarp and some sort of bug protection as well as the hammock. Using the bivy is simple enough; waterproof, bug protection, and can be used anywhere. Just my opinion. Matt