After much imagining and several thought experiments involving the concept of "blanket to coat", I decided it was about time to test my ideas in real life with a mockup. I cut midriff length left front, right front, and back pieces for a shallow V-neck sweater, trying to use as little of leftover blanket poncho fabric as possible. I didn't bother to match stitch patterns on the pieces because it would've required more fabric, and I'm saving the rest of the blanket for... something. I didn’t cut sleeves.
The band in the left picture is cut from the blanket's side edge. The band is cut as a separate rectangle, independent of the front. I was careful to cut the band wide enough (beyond the sideways mock ribs) so that the seam allowance would be far enough away from the front opening. The band was sewn to the sweater front edge and neckline. I kept the needle down as I turned the corner and stretched the band around the V. Because I was using a finished blanket border, the band is single thickness.
The pic on the above right shows the band and front cut as a single piece like in the diagram below. If I had cut a full length piece, bottom and side borders of the blanket would be preserved. The band was stretched around the V and then stretched along the neckline. This band is also single thickness.
Ok, this wasn't a controlled experiment; I didn't just change one element. I was also trying to make something I think looks good. As I pinned the one-piece (right side pic) together for sewing, I decided I needed to make the stitch pattern blend into the band a little better. I extended the neck seam and made a tiny dart where the seam begins, right at the place where the front band becomes a neckband. This ended up giving the neckline more of a curve, which I hadn't anticipated for some reason.
The important part I learned is that due to the stretch of this sweater knit, it is possible to cut a workable band and front as one piece. The particular stitch pattern design and finished edges of the blanket will, of course, impact the eventual design of the sweater coat when cutting a front and band as one piece. Cutting the band separately will give more options in pattern placement. (For those who like the design of this stitch pattern, the cotton cable blanket panels are available in the shop again.)
I still don't know which side I prefer as far as style goes, but the one-piece version in the picture on the right was definitely faster. Your thoughts?
(ETA CF Contributor Danielle decided on a hoodie, installing a zipper and a hood on hers, a different approach entirely!)