These don't seem to really be lined up with the strings.  Could you adjust these?
![screenshot 2014-04-26 23 11 31](https://cloud.githubusercontent.com/assets/5498859/2810385/c37e4692-cdb9-11e3-9bad-fb5b4d29be4c.png)
It might even be good to move them a bit to the right, so they're on the edge.