This vest can be made using all sorts of yarns.
Chunky yarns will not drape as well.
Experiment with different yarns and textures for a look that is uniquely your own.
No gauge is required, but you want a drapey feel, so the bulkier the yarn, the larger the needle.

This vest is knitted from side to side. I used a sport weight/fingering weight mohair/wool/llama single. The length of the vest will be determined by your yarn and needle sizes.