Originally Posted by
Polliwog
Flannel shrinks significantly enough that it should be washed and dried at least twice. The poly batting will not shrink. My favorite batting for most quilts is Dream Cotton Request Weight - very light and drapes well, even with flannel on both sides.
This was my first thought. I you plan on using batting or for that matter a second layer of flannel in the place of batting, wash all flannel first so it can do it's shrinking before you start creating your quilt.