Needles size changes: 2 mm for toe and foot. 2.5 mm from start of gusset. 3 mm after heel for whole of ankle/calf and top rib.

Looking at the reverse of the lacy rib in this pattern (last photo) has made me ponder because it is also attractive. I wonder how feasible it would be to knit reversed in the round (I use magic-loop). I am pondering how you would reverse YO, SSK and K2tog. K and P are more obvious.