This hat pattern includes charts - you can see that the argyle motif gets steadily smaller in size as you move up the crown.
Large motif; smaller motif; then first round of decreases and smaller motif; etc.

I used M-5 in natural & BabyFace here, but you could also use one of the new Plus Solids that coordinate with Mochi+

PS I personally adore corrugated rib and how it previews and shows off your colors, but you could do a plain rib in either yarn if you preferred.
I am still thinking about what colors to make my 2nd version as my DH wants one of these hats NOW “but not in girly colors”. LOL - he nabs every single hat i make! unless i make them ‘girly’ i don’t have any for moi!