So, these socks have definitely proven my lack of infallibility! Really, my only problem was a measuring mishap. I'm still not exactly sure how it happened. One row I still had 2.5 inches left to knit (so, half an inch 'til I needed to start decreasing for the toe), next row I had an inch left; and as I am not one for undoing knitting, a.k.a. frogging, I just decided to do custom fitted toes for the "right" and "left" socks, as pictured here:
Also, the pattern has a written mistake for which row to end on for the different sizes before starting the top foot chart. You should end on row 8 for the small sock, row 4 for the medium, and row 8 for the large. This mistake led to a late start on the top foot chart, and it is one of the reasons the last point is all the way at the toes. Oh well...
I'm not ecstatically (for some reason I always pictured that word as spelled with an "x", well it's not, according to spell-check!) pleased with how these socks turned out, but I still really like them. And, despite the color saturation difference between the beginning and end of the skein, I am still really pleased with the yarn. I still have at least a quarter of the skein left over. This yarn is worth it for the money you spend.
Here is the finished product:
And here is what I did with changing out needle sizes.
CO with US 1 1/2. Knit ribbing and one repeat.
Switched to US1 for 2 repeats.
Switched to US0 for 4 repeats.
Switched to US1 for 1 1/2 repeats, heel turn and gusset.
Switched to US0 with 41 sts on the bottom of foot, completed gusset decreases, and knit 5 repeats (starting with row 5 of the pattern) 'til starting foot chart. Obviously I should have done a few less.