I ended up sandwiching, quilting and binding it exactly like a regular quilt, but using flannel instead of batting. The flannel wasn't quite wide enough, so I just sewed pieces together and pressed the seams open. You really can't tell on the finished quilt.
I wasn't expecting the prewashed flannel to wrinkle this much, and I'm not sure I like it, but it does have a really nice weight. I actually think it would be a good choice to use in a summer quilt or bedspread.
The finished tablecloth is about 50" x 68". There are eight stacks of 22 coins, each coin measuring 2" x 6" finished. The sashing between stacks is 2" finished and the exterior sashing is 3" wide.
I didn't end up prewashing my Far, Far, Away (double gauze) because I was concerned that it would ravel excessively and/or get warped in the wash. Fortunately, after being sewn into the quilt, it washed beautifully.
Here's a shot of it on an actual table. I just love the color gradation! I used four coins each from 44 different Heather Ross prints. The sashing is one of my favorites -- Essex cotton/linen in Putty.
Sarah's favorite print was the Matroyshka dolls from West Hill, so I used that on the back. It wasn't quite wide enough, so I added a strip of Heather Bailey Bijoux along the edge. The binding is a leaf green Kona cotton (not sure which color).
I had originally been planning to use another stack of "coins" on the back, but decided that it would be too busy. As a result, I have a set of 44 coins left that I'd like to send to someone who could use them. If you have a use for them, leave a comment on this post and I'll announce a winner tomorrow.