Reserve 80 inches for the bind-off on the medium size, and you can knit every inch of your yarn to that point.
I’m a few rows shy of the full length (11 inches rather than 12), using all 109 yards of this skein. This means I can get a decent-sized snood from other single skeins of Knit Picks Comfy Worsted; Lion Brand Wool-Ease will have enough for a larger size with yardage to spare. But I’m not crazy about the Comfy for this project; there’s no resiliency to the Comfy: stretch out the ribbed section and it stays stretched.
I’m following the pattern and using the recommended needle size.
Final is 11 inches long (unstretched), and I knitted 65 or so rows before I hit the end of the yarn and needed to bind off; pattern called for 69 rows. (And that “65” is an estimate; I’m not sure I clicked my row counter every time.)
Note that when you cast on, you’re knitting the top part of the snood; the cables to tighten the circumference are the midpoint of the snood; the buttonhole slit for a leash comes after the cables, and any extra (or not-knitted because out of yarn) rows fall at the bottom end of the snood.
Finished snood sold for $64 in the GAN auction.
(Restarting on 26 May 2012: Had a circular that was uncomfortably just-too-long and was distorting the knitting. {Next time: Hiya-Hiya interchangeable tips with short cable; not fixed circular.} Also, I’ve found I’d rather C4F than C4B on the cables when I’m cabling without a cable needle. And--as if I needed another problem--I dropped a stitch and had no interest in fixing the drop while the existing problems were still around. I’ll change to C4F on the redo.)