Something like the attached?
Come at it from another angle...
You've found the customisation tool, and the correct template to edit, so, you click the "Add" button, and choose "Expression".
In there, type away. At its most basic, you could type along the lines of...
Duration: [Duration] • Rating: [Critic Rating]
But, as it's expressions we're using here, you can get quite creative. You could colour the text, you could perform tests so that different info appears under certain situations, and so on.
If you start off with that basic line, and also remove the existing Rating and Duration entries, that should get you up and running.
Hope that helps a little.
-marko
