Originally Posted by MAD777
I used the Magna 1.0 as a top cover for my WBBB and it definitely holds some heat!...
As did I. I sent the fabric to AHE and had them make my BBO with it.
While it definitely blocks a fair amount of breeze and holds a useful amount of heat, those asking need to understand that the tighter the weave is and the heavier the fabric is, the warmer it will be (even a bug net blocks a little wind and holds a "little heat").
With that said, the Magna "1.0" ACU has a very nice balance of heat retention vs. breath-ability for my
use. I am going to try a cotton muslin fabric (have a roll for other uses) for well below freezing use. It may be a bit too loose of a weave...time will tell.