Keep the shape simple
Hats, cowls and short scarves let the yarn show without burying it in tiny stitch details. A plain rib, stockinette or simple crochet texture can do plenty at this scale. Check the pattern measurements before you start; a super bulky fabric can grow wider quickly if your gauge is loose.
Swatch for warmth and fit
Zoomy Wool contains wool, so I would pay attention to how the fabric feels against skin and how the finished item needs to be cared for. Work a small swatch in the pattern stitch and measure it after treating it as you will treat the finished piece. For a hat, I would rather spend that time now than find out the brim is too loose later.
Count length, not balls
Thick yarn can have much less length in a ball than a lighter yarn of the same weight in grams. Compare the pattern yardage with the exact Zoomy Wool ball in Ribblr materials, then round up to whole balls. The ball count guide has a worked example.

