Doing a peasant heel in colorwork gives another explanation of why you want to start with the “leg side” heel stitches. On my sock, the colorwork pattern is continued down the heel, and you need to knit that leg side row first so it matches the first foot side row. A good way to learn that lesson, because I’d notice right away if the patterning were off because of starting in the wrong spot.

Thanks so much for the tutorial. I think for my next sock, I’m going to insert lifelines right before and after the scrap yarn rows. I assume that will take the place of threading a needle through before taking out the scrap yarn, without having me go blind trying to do so with tiny dark stitches.