You will need to detect the platform, etc using Unity functions. There are many different ways of doing this, eg. detecting screen size, detecting device by name, etc. Check the unity forums / answers for more details on what you can do to detect this. The override system is specific to the camera, and doesn't tie in with the platform switching at all - the 2 systems are independent to one another.
If you switch to the General tab, it'll tell you that the tk2dcamera can't detect the resolution. In the game window, you should use a fixed resolution rather than an aspect ratios, or simply choose the resolution to simulate in Presets.
By switching overrides I mean change the scale modes mainly. The offset isn't really going to affect the result as much.