I've been thinking for some time that Listsib JoVE is right, and I can make better-fitting socks by adding some stitches for a gusset. So I decided to experiment with the current sock project: a pair made from some gray and taupe Trekking XXL adapted from the Wyvern Socks pattern.
All was great for the increases. Almost an inch before I was ready to knit the heel, I began adding stitches on either side of the instep, increasing every other round for 14 rounds. I could tell by slipping it on that the fit was greatly improved. I made the heel, and then began decreasing. That's where things went wrong.
The red lines are there to highlight what I don't like. The ridge created by the increases suddenly angles to the left. And notice how the stitches to the left of the increase/decrease ridge seem to curve around, forming an arch? Yuck.
I think I'll be happier if I decrease someplace other than the point where I increased, maybe seven stitches over, on the "heel" side rather than the "instep" side. But getting back there is going to be painful, slowly un-knitting (or tinking) back to before the decreases I dislike.