You will need seven buttons. Rowan used # BN1979 from Bedecked in the UK.

Finished measurements:
Bust circumference: 35.5(39.5, 43.25, 47.5, 51.25)” 90(100.5, 110, 120.5, 130) cm
Finished length: 19.75(20.25, 20.75, 21.5, 22)” 50(51.5, 53, 54.5, 56) cm
Sleeve to underarm: 17.75(17.75, 18, 18, 18)” 45(45, 46, 46, 46) cm

Yarn used:
Rowan Summerlite 4 Ply
A. 418 Washed Linen - 5(5, 6, 6, 6) balls
B. 431 Pepper Pot - 1(1, 2, 2, 2) balls
C. 429 Navy Ink - 1 ball for all sizes
D. 438 Sand Dune - 1(1, 2, 2, 2) balls