What size should I grind..Fine or Coarse?

What size should I grind..Fine or Coarse?

Hi,

I make two kinds of breads; Tartine and No Knead (ken forkish)

I grind my whole wheat portion that I add in with my “country living mill”

I never understood what size I should be grinding my whole wheat flour to.  Sometimes I grind it where it feels like sand and other time I grind very fine (feels like flour)

Which is better for my types of bread?

Which is better for wild yeast?

Which is better for instant yeast?

Thanks!

Source: Fresh Loaf