Android/IOS GUI Rescale

Hey guys, I was wondering if anyone could help me with this. I am doing a phone game and would like to rescale all the GUITextures to the Phone screen size. I hear it can be done automatically and have found this script:

 var horizRatio = Screen.width / 800;
 
 var vertRatio = Screen.height / 600;
 
  GUI.matrix = Matrix4x4.TRS (Vector3(0, 0, 0), Quaternion.identity, Vector3 (horizRatio, vertRatio, 1));

If it is right, should i attach it to a gameobject in each scene or what? If anyone knows anyother way to do this or a non automatic way I would be really grateful. If you want I'll put your name or what you want in the credits of the game if you can help. Thanks :D