I do my socks kind of the same way. I cut my ribbon 6x the length of the top end of the sock... I make alldifferent size socks and 12" seems to be the norm because it must be the brand, but all my socks are 2" (2x6=12)
Once my ribbon is cut and heat sealed I fold the ribbon with the wrong sides touching and stitch it with a 1/4" seam.
Mark the back of your sock with a stright pin (the boutique I sell to prefers the seams on the insides of the socks, so wherever you want your seam) mark there
Keep your sock INSIDE OUT and place it over the arm of your sewing macine with the straight pin right under your needle.
Keep your ribbon inside out and pull it around your sock with the seem lined up with the straight pin (purpose for this one step is so you don't have a seam down the front of your super cute socks
Put you machine on the zigzag stitch (I use my tightest zigzag stitch, but I'm not sure if that really matters)
•With my left hand toward the back of the machine I pull the ribbon and with my right hand towards the front of the machine I keep the sock snug.
I really hope this makes sense, if not let me know, I have pictures around here somewhere.
(the only reason I don't use the Ribbon Retreat method is because your seam will show)