These bivies with cuben on the bottom look great!
I haven't sewn any. I am hoping to get started with a Silnylon bottom bivy this winter (to test in the Spring), and if it goes well, perhaps my next bivy will be made with cuben.
Were there special considerations you had to make when sewing the cuben? My understanding is that when making tents/tarps, there are certain design considerations that have to be made so that the cuben does not fail at high stress areas.
Obviously, areas of high tension & stress would not be expected on a bivy, but I was wondering what other issues people run into.