You may wish to use circular needles in both sizes, for the front and back.

Finished measurements:
Chest circumference: 43.75( 47.75, 52, 55.75, 59.5, 63.5, 67.25, 70.75)“ 111( 121, 132, 141.5, 151, 161, 170.5, 180) cm
Finished length: 26.5( 27.5, 28.5, 29.25, 30, 30.5, 31.25, 32)” 68( 70, 72.5, 74, 76, 77.5, 79.5, 81.5) cm
Sleeve seam: 17( 17.75, 18.25, 19, 19.25, 19.25, 19.75, 19.75)“ 43.5( 45, 46.5, 46.5, 49, 49, 50, 50) cm

Yarn used:
Rowan Norwegian Wool
A. 018 Ribbon Red - 2(2, 2, 2, 2, 2, 3, 3) balls
B. 013 Coastal Fjord - 6(6, 7, 8, 8, 9, 9, 10) balls
C. 014 Cloud Dancer - 5(6, 6, 7, 7, 8, 8, 9) balls