I'm still using my favorite fabric (flannel) and I used another piece of flannel in the middle of the square "sandwich." I used 5 inch square blocks and a 1" seam allowance on each side. Yes, that means the end measurement of the block was 3" square.
It produces a dense, warm (heavy) quilt with lots of rags. I'm not sure I would do a 1" seam allowance again, and if I did, I would definitely start with a minimum size of 6" square block. This is still a very pretty quilt, but it takes a lot of squares to get to a crib or toddler bed size.
One very cool trick I learned was the stitch I used to make the "X". I used a "S" curve, which I bet is a stitch on almost every sewing machine. By using the "S" I ended up with an effect on the smooth side of the quilt that I really love (and didn't anticipate).
My picture is not great, but each block matched curves and I didn't do anything special in using the "S" stitch. Here's another view that might be a little better
I still like these rag quilts and can't wait to try more variations. Next time I'll try some big squares. My sewing machine will thank me.
If you are looking for more basic tutorials on rag quilts, check out my post here. I also have some additional tips on making rag quilts here.