I love Craftsy classes, and Amy Herzog's are my favorite of them all. I'm watching the third of her classes, which is sort of a prequel for her custom fit class.

It's a super informative class, discussing how to choose the right size — and make needed modifications — for all different kinds of sweaters. The class pattern is a drop-sleeve sweater. This is a very traditional shape, and I think of it as unflattering and old-fashioned.

But Amy says a drop-sleeve pattern needs 4-8 inches of ease to look good. A set-in sleeve requires only one or two inches of ease. A raglan sweater takes 3-6 inches. Knowing this could make a difference.

Her measurements are actually the same as mine in her upper torso and bust, and the class pattern looks great on her. I could make the class sweater in the Venus Blue Prism yarn.

A drop-sleeve sweater, Amy says, is best in a light, drapey yarn. Prism is that.

This is such gorgeous yarn, wool and silk and exclusively sold at a yarn shop in Colorado. It's the same yarn I used for my first Ketch, in a different colorway.

Can I take a chance with such a special yarn?

I have plenty of time to think about it, because I am in the middle of the second Ketch. And Ah la Fraise. And Chimera. and Adiri. I also plan to make a triangular lace scarf at last this year. And a tank or tee to make a twinset of the first Ketch.

I enjoy thinking deeply about these things. I could also swatch to help my decision. This class is very bold on the subject of swatching. We lie to ourselves, Amy says, when we swatch. She does a lot of math in this class, and I am becoming persuaded.

Usually, I wouldn't make a big swatch and wash it because that will take up so much yarn. I might run out, after all. That is the worst thing! Especially with a hand-dyed yarn. It might be impossible ever to get more.

But I may change my ways. If Amy is right about ease for set-in sleeves, my second Ketch is going to be significantly too big.