I have bought the dri-ducks poncho that serves as a weather shield for the JRB underquilt. I have found it more necessary in foggy conditions than rain, my tarp does a good job there. Here is the rub, I have a great waterproof outershell that I use when it is raining, don't really need the poncho but I like having the shield for the quilt.
So here is the question/dilemma. Is there some sort of fabric that I could use to fashion a "vapor-shield" for the quilt that at the end of the day would be lighter than the poncho?