I followed instructions for the yarn weight 2 version.

My stitch gauge was spot on (29 sts/10 cm), my row gauge was way off (38 rows/10 cm)

Modifications:

• used more colours
• also used several shades for the MC
• increased to 156 sts after the ribbing (instead of 144, which I find a little tight for my head at this gauge)
• decreased to 144 sts after chart B (instead of 120)
• worked three more stripes of diamonds after chart B
• since I now had 144 sts, I worked the decrease chart six times instead of five.