I did not use the “twined” knitting method because I hated the twisting and then untwisting of the yarn. And as long as you don’t carry the yarn for more than 4 stitches it works out just fine.
Did not use 2 circular needles but just 1 with long enough cable and knitting magic loop method.
I also did not knit the graph all the way to the end because the toe got pretty pointed that way. I stopped when there were about 18 stitches left (9 for the front and back) and then Kitchener stitch to close. That made the front of the slipper more rounded.
Made a men’s pair (last pic) with Basic Pattern and using leftover yarn from the other slippers.