additional gauge:

1x1 rib 5 rows/rounds = 2cm
colour work 20 st x 34 rounds = 10cm
garter st 20 st x 38 rows/rounds = 10cm

The pattern suggests the following colours:

250 (300) 350g of white (0001)
100 (100) 150g of each orange (0027), green (0092), lilac (0046), yellow (0043), petrol (0072) and violet (0012)