I imagine the three tops, side by side -- a stiffer Small, a mellow Medium, a looser Large -- and feeling each fabric to see which I liked the best.
I used to think that there was a perfect gauge for each yarn -- usually the one printed on the label. Changing the gauge seemed like a clumsy way to size a pattern
But lately, I'm finding that gauge can be a personal preference, an evolution, even. I've been crocheting my hats tighter than I did three years ago. I try a chunky yarn at a worsted gauge. A heavy worsted yarn at a light worsted gauge.
A year from now, my hats may be able to stand up by themselves.
Or they may go in the opposite direction. Soft, soft, soft. And see-through.
It's all in the gauge.
NOTE: This is the sixth in my "Hundreds of Hats Later: What I've Learned" blog posts. Next up: "Taming Novelty Yarns."