You will need 4(4, 5, 5, 5, 5, 5.) buttons. Rowan used #BN1365 from Bedecked in the UK .

A small amount of same (or similar) yarn in shade 120 Anthracite is needed for embroidery.

Finished measurements -
Chest measurements: 22.75(24, 24.5, 25.25, 26, 26.5, 28)“ 57.5(61, 62.5, 64, 66, 67.5, 71) cm
Finished length: 8.75(9.5, 10.25, 11, 11.75, 12.5, 13.5)” 22(24, 26, 28, 30, 32, 34) cm
Sleeve length to armhole: 4.25(, 6, 6.75, 7.5, 8.5, 9.5)“ 11(13, 15, 17, 19, 21.5, 24) cm

Yarn used:
Rowan Cashsoft Merino
A. Silver 106 - 2(2, 3, 3, 3, 4, 4 ) balls
B. Cream 102 (1(1, 2, 2, 2, 2, 2) balls
C. Taupe 104 - 1 ball for all sizes.