I just invented a mystical Cuben product code.
My thoughts are by sticking to 2K, weight is kept relatively up at about 1.25oz/sqyd.
1K would take that down to around 1.0
1K would still be more than strong enough for shelters. The .18 Mylar would help with long term durability particularly HH.
It also brings it down light enough to think about other things, like potential in vapour barriers…if its too heavy then the small advantage it might provide with reflecting human heat is not worth the overall weight of the material vs a much lighter vapour barrier material.
With .18 mylar it would also be suitable still for groundsheets. 1K is more than strong enough for them.

