Ilike using flannel for baby's tummy-time quilts. And yes, it will usually distort after washing and drying. I never thought of using wider seams tho. Are you afraid it will fray out? I've never had that problem.

That's a really good question about purchasing additional yardage. I have never knowingly done it and yet I have never run out. Hmm.

Play with a small amount first. Do a test run.

I use flannel for backing and I also piece it. Big blocks. I'm doing a crazy quilt backing right now. Flannel's not difficult. You just have to get used to it.