My sock gusset is done and now I've begun the foot! The gusset knitting was surprisingly easy. And in the words of a famous sleuth, "Elementary my dear Watson".
I placed a marker on each circular needle at the point where the decreases would occur. On #1 needle the decreases were K2tog, and on #2 needle the decreases were SSK.
Decreasing gusset stitches continued for just 19 rows. And here's the end result:
Stay tuned for Step 5 - Knitting the Foot!