You will need 4 buttons. Rowan used 1” (2.5 cm) leather buttons.

Finished measurements:
Bust circumference: 32.25(35.75, 40.25, 44.5, 47.75, 52.25, 55.25, 59.75, 64.25)“ 83(91, 102, 113, 121.5, 132.5, 140.5, 151.5, 163) cm
Finished length: 34.75(35.5, 36.25, 37, 37.75, 38.5, 39, 39.75, 40.25)” 88(90, 92, 94, 96, 98, 99, 101, 102) cm

Yarn used:
Rowan Tweed Haze
Shade 554 Tornado - 5(5, 6, 6, 7, 7, 8, 9, 9) balls