There is no yardage that I can find on the DMC Cebelia Cotton Size 20 thread. I used a 50 gram ball.

These are the rest of the materials needed for pattern

24 AB 3mm crystals
Toho 11/0 Rounds 1954-124, dyed rainbow Violet (7.5) grams
Silver plated Twist Cable Chain 13x3mm (5 ft in length)
4 jump rings and 2 clasps (screw type clasp)

One size fits most however pattern can be increased or decreased just by simply measuring how much chain you need to for your foot size. Just follow the pattern and end it where you need to for size.