Wow... the heel flap actually worked! I have a beautiful salt-and-pepper heel, normal-sized gusset stitches to pick up, and heel stitch! I can hardly believe it!
I realized that you could swap rows 1 and 2 with rows 3 and 4, and then you could apply this technique when doing two-color stranded work, without necessarily having to cut the yarn.
I wonder if I should post my discovery to Socknitters or something.