Pretty sure the gauge is screwy on this pattern. I made a swatch(which I neeever do, I know, I know) and although it was exactly 4”“ in height. it was over 4” in width. .
I am reading a lot of notes on this about the soles being thin and the tops too big. Getting a bit nervous about the fact that I spent the better part of today working on these. Whelp, just might make an extra sole while my others damp dry. (Ugh, really don’t want to). I blocked my soles so they wouldn’t be all curly when trying to attach it to the tops (and for sizing, my feet are ginormous).
Or maybe just sew rubber no skid to the bottoms? I have really slippery floors.

Anyhoo. I used a chainless sc foundation for the tops.
Didn’t fasten off when I was done with either, so I could attach them continuously.
What’s nice about the chainless foundation stitch, is that it gives you two nice strands to catch when seaming the toe to the sole.

Since there are no specific directions on how to attach the top to the sole, here’s what I did:
I found the middle of the toe and the middle of the sole at the top (between the “corners”). There were about 8 stitches on either side. I pinned the top and sole together.
Pinned the corners. Then counted 32 stiches on the sole from the corners on both sides and pinned together. (There are 32 rows, so 32-ish stiches).
Then I followed the directions from there!
You have to make sure you crochet into the end of every row of the top for this to work. If you don’t count it out, they may turn out all wobbly and uneven at the heel.

There are a couple of things I would do differently 2nd go round for sure, but had to repeat my “mistakes” on the second one so they would match but not many, other than beefing up the sole somehow.
(Do slip stitch around heel tighter AND do sc tighter to really get them to “stand up” against each other.)
Transition from sc around edge to heel needs work--doesn’t look right to me.
Also might try to tighten up the sc around the edge, so it’s not so sticky-outy.

Let me know if this helps anybody!