Yarrow's are one of my absolute favorite species. I've observed them in the wild, and they always go for rocky places. In my Yarrow's tank, which is a 30 long, I have the entire back of the tank covered with a 3D rock ledge. This is where they spend most of their time. I have other rock formations in the tank foreground as well.

They are lizards which like to dart around, so I would question your horizontal tank setup for them. I would think that would be for a more arboreal species such as anoles or chameleons.