I am looking at making a bivy eventually. I will be copying Andy's design with cuben bottom, and a breathable top.
I am curious whether I would be better off with a top made of Momentum 50 or SevenD. I am looking for breathable but also at least waterproof enough to deal with dew/condensation/short drizzle.
They both have very similar weights (.69 vs .64) so what is the difference between the two? I can't tell wich one would work best for a bivy, especially with the recent change between Momentum 55 and SevenD being new, there are very few field reports of either.