I also re-wrote the pattern to work the back and sides top-down in one piece.

For the smallest size:
Yoke:
Cast on 30 sts
Row 1: k3, pm, k8, pm, k8, pm, k8, pm, k3 (30 sts on needle)
Row 2: k1fb, k1, k1fb, slip marker, k1fb, k to one before next marker, k1fb, slip marker, k1fb, k to one before next marker, k1fb, slip marker, k1fb, k to one before next marker, k1fb, slip marker, k1fb, k1, k1fb (40 sts on needle)
Row 3: k1fb, knit all across until one before last stitch on needle, k1fb (42 sts on needle)
Row 4: k across but k1fb before and after every marker (50 sts)
Row 5: k all

Repeat rows 4 and 5 five more times

Row 16: k across but k1fb before and after every marker (98 sts – 13, marker, 23, marker, 26, marker, 23, marker 13)
Row 17: k all

Body:
Row 1: knit to marker, slip marker, slip sleeve sts to scrap yarn, remove marker, k across back, slip marker, slip sleeve sts to scrap yarn, remove marker, knit (52 sts on needle)
Row 2: knit all
Row 3-X: Keep knitting garter stitch until entire piece measures 10 inches from collar
Bind off

Otherwise the pattern is the same, but the sleeves are slipped from waste yarn to dpns to be knit in garter stitch in the round. I almost forgot to alternate my knit and purl rows in the round to get garter!