I went to their website to check this out :D:D:D
You would have twice the bulk in the seam intersections. I would think that the whole quilt wouldn't be quite as supple either. Due to the fact that you are also using muslin as a foundation, and the extra layer of fabric I wonder if flannel would be better for batting? Unless you live somewhere where it gets very cold.
I wonder how easy it would be to quilt, by hand or machine?
I am intrigued as to how they have you stitch it down, the free patterns didn't show that part :wink: