You will need 5 buttons. Rown used # BN1709/15 from Bedecked in the UK

Finished measurements:
Bust circumference: 35.75( 39.25, 43.75, 47.25, 51.5)“ 90(100 ,111, 120, 131) cm
Finished length: 22.75( 23.5, 24.5, 25.25, 26)” 58(60, 62, 64, 66) cm
Sleeve to underarm: 17.75(17.75, 18, 18, 18)“ 45(45, 46, 46, 46) cm

Yarn used:
Rowan Cotton Cashmere
232 Charcoal - 7(7 ,8, 9, 9) balls

You may also use Rowan Handknit Cotton
Black 252 - 11(11 13, 14, 14) balls