I do plan to release a multi-size version of Skew later, but for the brave, I'm posting my notes on how to shape the heel for an 84-stitch foot. A talented friend successfully produced socks from these notes. If you need line-by-line instructions, I'm afraid you'll have to be be patient until the official version comes out.
KNIT AT YOUR OWN RISK. I have not personally tested these numbers and can't provide "pattern" support.
Cast on 8 stitches per needle, increase in the big toe section to 56 stitches, then to 84 in the mid-toe section.
Inner ankle gusset (IAG) needs to create 42 sts for the back of the leg, which takes 42 rounds (21 shaping rounds separated by plain knit rounds). After 7 IAG shaping rounds (14 sts between IAG markers), start working mini-gusset shaping as for the 72-stitch version. After 14 IAG shaping rounds (28 sts between IAG markers), start the heel decreases.
During the heel decreases, my notes say there should be 18 stitches between markers instead of the 15 for 72-st version-- so on left sock, replace "k 10" with "k 13."