I have a couple questions regarding my chair rail installation. I have read that, if possible, the chair rail should be at the same level as the window sill but I am thinking it might be better a little higher. Note that the overall wall height is 8'4", the upper surface of the window sill is around 31" and the height of the chair backs is around 36". One of the photos shows how the chair rail would look if it were installed a few inches above the window sill.

I would be interested to hear what others think about this.
Another issue is that I want to terminate a chair rail about 1 foot beyond an inside corner as it reaches an outside corner about 13 inches to the left of the inside corner.

I was thinking of putting in a mitered return about one inch from this outside corner. Another option which is easier would be to not even install the railing along the 13 inch wall and just terminate the molding in the inside corner using a square cut. I'm not sure if this would look as good though.