You will need 6 buttons. Rowan used # BN1562/20 from Bedecked in the UK.

Finished measurements:
Bust circumference: 39.5(43, 47.25, 51.5, 55” 100.5(109.5, 120, 130.5, 139.5) cm
Finished length: 29.5(30.25, 31,32, 32.75)“ 75(77, 79, 81, 83) cm
Sleeve to underarm 18.5(18.5, 19,19, 19)” 47(47, 48, 48, 48) cm

Yarn used:
Rowan Felted Tweed
A. 177 Clay - 7(8, 9, 10, 11) balls
B. 205 Lotus Leaf - 393, 3, 4, 4) balls