In helping a fellow knitter with smaller feet, I've managed to work out the following to make a smaller "foot" portion of the sock.
Specifically, johussion measured her foot and got to a completed toe that is made up of 52 stitches. Looking at the STR pattern, there's an approximately 25% increase in stitch count from toe to foot to compensate for the rib and the smaller needle gage. Doing some simple math gets us to a target of 64 stitches all around for the foot (52 stitches plus 25%).
Here's the hard part - given the [p1, k2] rib on the instep and the [p2, k2] rib on the sole, it take a little fiddling to work it out. Also, the set-up row is done in groups of 7 and 8.
Using the "new math", I ended up with this for the next two rows:
Set-up round: P1, [k2, p1, k1, kfb] 5 times - 31 instep stitches. K1, kfb, [k2, p2, k1, kfb, p1] 3 times, k2, p1 - 30 sole stitches, 61 total stitches
Round 1: [P1, k2] 12 times, [p2, k2] 6 times, p1
Now, the instep will have 10 k2 ribs and the sole will have 8 k2 ribs. Knit away and turn the heel a little later - likely at 1.5" from the heel rather than 1.75", given that we're working with a smaller number of stitches overall.
Last part of the pattern is for the leg and it's worked in repeats of 24. That means trouble. We've got 61 stitches coming off the toe - and that's 13 more than two repeats and 11 less than three repeats (standard pattern has 3 repeats). Should you will fill the gaps with purl stitches? Increase around the leg to get up to 72? I really don't know. I suspect johussion and I will figure this out when she turns the heel. It's all about the sizing, you know.