I figured that I have the shaping and the fit down, so I no longer need the additional stretchiness of the knit rib.
So I replaced the knit part with 2-ended tunisian crochet, worked in the round.
That worked, but I must have been out of my mind when chose the yarn. It would have just been a bit garish if I’d been knitting them, as you can see from the inside:
But the effect of the forward and reverse passes is pretty alarming:
I’m pleased with the fit and the bulge at the top (that I got by swapping in a Purl stitch in place of a narrower stitch–it’s not folded).
I’m going to try this again with less colorful yarn and a K-TopKnot/(2 Twisted Knit) rib combo. (The K-TopKnot is the only K/Knit stitch that’s easy to do in 2-ended tuni crochet, where you find yourself working with the back of the return chain).
So the Sock Saga continues…