I use small. I've used two fantasias on my character during my duration in XIV. One was the free one that I used to try out a Highlander, the second was to change everything back. When I changed back though, I didn't revert 100%. Her iris size, eye color, and height remained altered from her first iteration. I changed her iris size from large to small and also adjusted the shade of purple in her eye color to get them to be more 'piercing'. I also adjusted her height to maximum. I wanted to create an attractive character while also avoiding making her look like a loli, and more like an adult.

The large iris size in particular really bothered me during cut scenes that zoom in on my character's face.