Relative screen positions.

Hello. In anticipation of porting my project to multiple devices with different resolutions, I decided to base all transform positions off of the screen coordinates. For example, if I want to spawn something just outside of the user's view I would find the position of a point 1/8 of the screen's width past the right side of screen and then instantiate the object there. This simple script I created is an example of that (it always places MyObject in the upper right corner of the screen). My question is this: is this a good idea?

 var MyObject : GameObject;
 var corner : Vector3;
 
 function Start () {
     corner = camera.ScreenToWorldPoint (Vector3 (Screen.width,Screen.height,10));
     MyObject.transform.position = corner;
 }