I have made a few down 20* topquilts with box baffles, etc using calendered fabrics from RBTR memberance fabric line. However I am currently looking to make myself a 40* topquilt using Apex Climashield insulation for warmer weather when humidty and damp spring east coast conditions are a concern. My question is whether or not there is a significant reason to use calendered fabric for the outer shell of a topquilt. My underquilts all use calenendered fabrics, but TQ is in the hammock under the tarp so wind doesn't seem like as much of an issue. The reason I want to use uncalendered is so that I can make the shell from a single piece of 1.0oz HyperD. My thought is to order a 5yd length of fabric and fold it in half. The folder edge would replace having to sew the seam at the head end of a simple Apex quilt.