What a fun hat! The pattern is well explained with great videos and clear picture tutorials for special stitches. Great for leftovers.
Working with yarn from my stash, I’m glad finally to use up some of my oldest yarns.
My gauge is slightly tighter, but the hat fits me perfectly.

Test thread

Measurements washed and laid flat:
Circumference: 48 cm
Total length: 19 cm
Brim length: 5 cm
Body length: 9.5 cm
Crown length: 4.5 cm

Gauge washed:
Stitch gauge: 4 diamonds = 8 cm. 10 sts = 10 cm.
Round gauge: 20 rounds = 10 cm

Needles:

• 8.00 mm for the brim, Addi interchangeables (short needle set, 40 cm length)
• 9.00 mm Addi circular, 40 cm length. The crown was worked with two circulars.

Yarn used:
MC Viking Balder:
(1) 25 g, used up. (2) 74 g, (56 g left).
Used total: 25+18 = 43 g.
0.43 skeins = 36.6 meters (40.0 yards), 43 grams.

CC Garnstudio Fox:
(1) 19 g, used up. (2) 13 g, used up. (3) 50 g (48 g left).
Used total: 19+13+2= 34 g.
0.68 skeins = 31.3 meters (34.2 yards), 34 grams.

Other notes:
I used the Russian Join to attach new yarn. I found it best to avoid joining yarns on pattern round 1 where the increases are made.

Page 4, right paragraph: I needed to work 1 extra repeat to get 13.5 cm height. Meaning that I repeated rounds 1-4 two more times instead of 1.