The socks are done, and are just lovely:
Like many others, I noted that there seemed too be too many stitches. So I left out one entire repeat, working the leg with 60 stitches. I left 35 stitches for the instep, and increased the remaining 25 heel flap stitches to 30.
Apart from that, I worked them in the usual top-down gusseted construction, keeping the slipped stitch pattern all along the sole as I usually do, for added wear-resistance. On the toe, I continued the ribbed pattern on the instep for a smoother visual transition.
Despite using more yarn for the heavy-duty sole, I still have 20% of the skein left. I’m getting quite a little collection of sock-yarn leftovers; time to start hunting for scrap-busting patterns!