Convert gameObject position on screen

Hello, I would like to create 6x6 board with toggleable sprites. They should be next to each other. On andEngine I base on anchorCenter which is (.5f,.5f) by default in every new object.

On andEngine I arrange it like this

 for (int i = 0; i < BOARD_ROW; i++) {
     for (int j = 0; j < BOARD_COLUMN; j++) {
         Letter rLetter = rollLetter ();
 
         float texWidth = rLetter.sprite.rect.width;
         float texHeight = rLetter.sprite.rect.height;
         Debug.Log (texWidth + "x" + texHeight); // 50 x 50
 
         //Here I'm not sure which convert I should use. 2.5f because it's 2.5 texture width (50*2.5) form layer/scene center. It would be .5 if I want 2x2 board.
 
         rLetter.position = Camera.main.ScreenToWorldPoint (new Vector2 ((-(texWidth * 2.5f) + (texWidth * j)), (texHeight * 2.5f) - (texHeight * i)));
         lettersOnScreen.Add (rLetter);
     }
 }

And I got some thing like this

I can live with (0,0) on down left corner but space between sprites is too big.

Letter class

 class Letter
 {
     private GameObject gameObject;
     public Vector2 position {
         get {
             return this.gameObject.transform.localPosition;
         }
         set {
             this.gameObject.transform.localPosition = value;
         }
     }
     public Sprite sprite {
         get;
         set;
     }
     public BoardPosition boardPosition {
         get;
         set;
     }
     public float likelihood {
         get;
         set;
     }
     public Range likelihoodRange {
         get;
         set;
     }
     public string code {
         get;
         set;
     }
     public bool clicked {
         get;
         set;
     }
 
     public Letter ()
     {
     }
 
     public Letter (GameObject go)
     {
         this.gameObject = go;
     }
         
 
     public Letter (Sprite sprite, string code, float likelihood, Range likelihoodRange)
     {
     
         this.sprite = sprite;
         this.code = code;
         this.likelihood = likelihood;
         this.likelihoodRange = likelihoodRange;
 
     }
 
 
     BoardPosition getBoardPosition ()
     {
         return boardPosition;
     }
 
     void setBoardPosition (BoardPosition boardPosition)
     {
         this.boardPosition = boardPosition;
     }
 
 }

Can you tell me what I'm doing wrong?