You will need 7 buttons. Rowan used # G422830 in copper from Groves and Banks in the UK

Finished measurements:
Bust circumference: 35.5 (39.75, 43.25, 47.75, 51.25)“ 90 (101, 11, 121, 130) cm
Finished length: 20.5 (21.25, 22, 22.75, 23.5)” 52 (54, 56, 58, 60) cm
Sleeve to underarm: 17.75 (17.75, 18, 18, 18)“ 45 (45, 46, 46, 46) cm

Yarn used: Rowan Selects Patina, 4 (5, 5, 5, 6) balls
Shown in Shade 415 Lustre