Yo uwill need 4(4, 5, 5, 5, 5, 5) buttons. Rowan used #BN1979/25 from Bedecked in the UK.

Finished measurements:
Chest circumference: 20.5(21, 22.5, 23, 23.5, 24.25, 25.5)“ 52(53.5, 57, 58.5, 60, 61.5, 65) cm
Finished length: 8.25(9.25, 10.5, 11.25, 12, 12.75, 13.5)” 22(24.5, 26.5, 28.5, 30.5, 32.5, 34) cm
Sleeve to underarm: 5( 6, 6.75, 7.5, 8.25, 9.25, 10.75)“ 13(15 ,17 ,19, 21, 23.5, 26) cm

Yarn used:
Rowan Baby Cashsoft Merino
A. SIlver 106 - 3 (3, 3, 4, 4, 4, 5) balls
B. Cream 102 - 1 ball for all sizes
C. Denim 112 - 1 ball for all sizes
D. Taupe 104 - 1 ball for all sizes
E. Heavenly 111 - 1 ball for all sizes