Nope. It’s not going to work. I need to accept that and move on. This morning I tried on the sock, everything in place but the toe. It’s too tight. I had to fight to get it on, and then when I took it off I had ribbing marks on my leg and foot. And the heel flap is too short. I’m giving up on the sock.
I don’t know anyone with feet as long as mine (women’s 10.5) but even narrower. And the heel flap would still be too short. So the next steps are: tear it out, skein up the yarn, skein it, wash it, dry it, re-wind it into a ball and start over again, with more stitches and less ribbing.