According to the pattern it's -
'Gauge: 3sts and 6 rows=1in on size US 5 needles'
According to the yarn manufacturer it's -
'3.75 sts per inch with a recommended needle size of US 10'
A size 5 needle with bulky yarn sounds like it would make the fabric too stiff to me, but who knows. :shrug:
So the answer is - your guess is as good as mine at this point. :lol: