Renee,
I have always heard you can't mix and match flannels with cottons because of the weights and shrinkage issues but I haven't tried it, either. My guess is that someone with experience could really give you the heads up. I imagine that it would be harder to keep your hexagons lined up and prevent puckering, if that is something you're interested in. Would love to see pics of the process!! I'm in the midst of the grandmother's flower garden. I see hexagons everywhere LOL :lol: !!