I just purchased a Hexamid tarp earlier last week off of gear swap, and quickly came to the realization that I will need a new bivy. I am currently using an older Equinox bag cover that is rectangular instead of being tapered. The Hexamid is only about 30in wide at the ends, so my current bivy hangs out like 5-6 inches. Doh!
I will always use the bivy paired with a tarp, so am looking for more of a minimalist bag cover than a full featured stand alone bivy sack. Obviously, the lighter the better, because if the bivy is too hefty, I might as well just use one of my larger tarps. My Equinox bivy weight 9 oz., so am looking for something around that. Not over 1 lbs. Montbell, MLD, or the like. Let me know if you have anything.