Oh, I wish I had found this earlier.........sorry you had to wait. I'm not sure if I can be of any help, as I usually wing it, and it's been awhile.
Number one, put in that lifeline right now........before you try it any way. Number 2, this is what I was saying, the reason I wasn't totally pleased with my Alex heel. I think I did like you said, and the slipped stitch was the wrong color. I'd try it a couple of ways, expecting to have to do it again if I didn't like the looks of it, but I know that every round/row that you get is a prize, with your hands the way they are. So, I was thinking that I would do the wrap thing, while I still have the sock's yarn color going, and then do the first actual row of the Sherman method with the new color.........I don't think that your suggestion would work, because you don't want your contrasting heel color to go all the way around the instep.