I don't use the flannel as the backing as it does lint, and the babies need only cotton cloth.
The sizes is 20x24, and I have been using a very simple pattern. 2-1/2 inch strips (2 colors) pressed open and cut 2-1/2 wide. Make a 4 patch. Then one different color 4-1/2" square. Alternate the blocks. No borders or sashings. Sew the binding on the back side and machine stitch to the front. I usually do FMQ as the quilts are laundered daily for the infection protection. Think of this like the Quilts for Kids that many of us are doing.