Set screen boundaries with code

Have you looked at Screen.width and Screen.height?

Um yes, here's my code:

 function Update()
 {
 
 //// $$anonymous$$ovement ////
     
     //set screen Bounds
  screenBounds = Vector3(Screen.width, 0, Screen.height);

     //set offset
     screen.x = (screenBounds.x*4)/100; //4% of screenBounds.x
     screen.y = Screen.height;

     
     //$$anonymous$$ove the player. 
     directionH = Input.GetAxis("Horizontal") * speed *   Time.deltaTime;
     playerPos = transform.position;
     playerPos.x = playerPos.x + directionH;
     transform.position = playerPos;
     
     
     //set players position in screen coordinates
     playerPosScreen = Camera.main.WorldToScreenPoint(transform.position);


     //transform.position = Camera.main.ScreenToWorldPoint(Vector3(playerPosScreen.x,screen.y,playerPosScreen.z));
     
     if(playerPosScreen.x > screenBounds.x-screen.x)
     {
         transform.position = Camera.main.ScreenToWorldPoint(Vector3(screenBounds.x-screen.x,playerPosScreen.y,playerPosScreen.z));
     }
     else if(playerPosScreen.x < screenBounds.x/2-screen.x)//not where I want the player at the moment, ignore this
     {
         transform.position = Camera.main.ScreenToWorldPoint(Vector3(screenBounds.x/2-screen.x,playerPosScreen.y,playerPosScreen.z));
         
     }
 }

So Basically, the code here works like I want it to if right wing of the player ship hits the screen boundaries, and cannot go further. This works fine and dandy on some aspect ratio settings, but when I switch to something like 16:9, half the ship is outside the screen..