Regarding the points you bring up in your video. To make the rows clamp you would need to add a value to the "NavigationRows" (int) property, in your example I believe you want the value of 1.
For the increased sizing you would want to either set the "SelectedItemZPosition" (double) with a value that moves your item TOWARDS your camera (generally positive number), or set the "SelectedOffset" (Point3D) with the Z being a number towards your camera (generally positive number)