Just a little too far right... remember the golden rule of thirds. You need 1/3 of the open space to be on the right of the pointy mountain-like rock. As for plant selection; hairgrass would work, but you wouldn't see much of the rock and perspective would be off a bit in my opinion. I would go for a shorter plant like HC or Glosso. A bit of a steeper slope would help too. I hope I'm not being too critical... you did ask... good luck.