GUI Button Transform Screenspace

Hey guys,

I'm a little new to scripting, so bare with me: I've made GUI Buttons spawn above a trigger when I enter it. I would like to transform ANOTHER button, above the same trigger, on the X axis via screenspace, not world position. So far I have world position working, but I've no idea how to convert it. I think I need to use WorldToScreenPoint, but I've no idea how.

I would like to control it with the buttonPickupOffset variable, so I can just slap some numbers into the inspector and move it at will.

Here's my code:

 var buttonPickupWidth: float = 50;
 var buttonPickupHeight: float = 50; 
 var buttonPickupOffset: float = 0; 
 
 var inArea : boolean;
 var isButtonPickupVisible : boolean;
 var pickedUp : boolean;
 
 var pickupSkin : GUISkin;
 
 function OnTriggerEnter (other : Collider) 
 {
     inArea = true;
     
     Debug.Log("You have Entered");
     isButtonPickupVisible = true;
 }
 
 function OnTriggerExit (other : Collider) 
 {
     inArea = false;
     isButtonPickupVisible = false;
 }
 
 function OnGUI()
 {  
     GUI.skin = pickupSkin;
 
     // calculate the world position for the button
     var pos3dPickup = transform.position + Vector3.right * buttonPickupOffset;
       
     // convert it to screen space
     var posPickup = Camera.main.WorldToScreenPoint(pos3dPickup);
      
         
     if (inArea == true)
     {    
         posPickup.y = Screen.height - posPickup.y; 
         
         if (isButtonPickupVisible == true)
         {                        
             if(GUI.Button (new Rect (posPickup.x-buttonPickupWidth/2, posPickup.y-buttonPickupHeight, buttonPickupWidth, buttonPickupHeight), ""))
             {
                 Destroy (gameObject);
             }
         }
     }
 }