Also, the silk is quite challenging to sew with because of how slippery it is, and because it gives quite a bit in sewing, rather than holding its shape. I was pleased that it ending up working out all right. I did a few small trials along the way, for one part or another of the process, and that helped. It also helped that I had some experience at this point with the fabric after sewing the scarves. (Double-clicking on photo should bring up a larger version.)
More about the process, mostly for the quilters out there: I pinned the batting to my design wall, and spray-basted the silk to the batting. (I am a big fan of spray-basting; see this tutorial by Patsy Thompson.) Then I trimmed the batting so that it was 1/4" less that the top all around. (See helpful tutorial by Susan Brubaker Knapp.) I taped the cordoroy backing to the floor of my studio, right side up. I laid the top and batting on it, pinned around, and then cut the backing to the same size as the top.
When I sewed the three layers together, I kept the batting on top, so that I could check that I caught a bit of it most of the way around the edge, using a 3/8" seam.
I left an opening, turned the quilt right side out, and then hand-sewed the opening closed. How then to mark the quilting? I didn't want to mark the silk, even with chalk. I thought of quilting with the cordoroy side up, as it could be easily marked, but I thought it likely the silk would then bunch up underneath. I ended up "marking" the silk by putting a line of straight pins where I wanted to quilt. This had the dual benefit of not only marking the quilt, but keeping the 3 layers together as well. (The top and batting were secured by the spray-baste, but the cordoroy needed pinning to those 2 layers.) You can see the white heads of the pins in the photo below.
When I was finishing the quilt, I suddenly noticed that--minus the light green--I had once again been using the colors of my "Shelter" quilt. Seems I'm not done with these colors. . .