Using SyncListString/Synchronizing lists

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine.Networking;
 using System.Linq;
 
 public class Player : NetworkBehaviour {
 
     [SyncVar(hook="OnPlayerIDChanged")]public string playerID;
 
     private GameObject[] loadCards = new GameObject[39];
     private Sprite[] loadSprites = new Sprite[39];
     public SyncListString usedSprites = new SyncListString ();
     private List<Sprite> sort = new List<Sprite> ();
     private SpriteRenderer sRend;
     private Transform tr;
 
     private void GenerateCards ()
     {
         loadSprites = Resources.LoadAll<Sprite> ("Sprites/cards");
 
         for (int i = 0; i < 10; i++) {
             loadCards [i] = Instantiate (Resources.Load ("Prefabs/Card")) as GameObject;
             //loadCards [i].transform.parent = GameObject.Find (string.Format("Player {0}", netId.Value)).transform;
 
             while (sort.Count < 10) {
                     var index = Random.Range (0, 39);
                     if (!usedSprites.Contains (loadSprites [index].ToString ())) {
                         CmdAddUsedSprite (loadSprites [index]);
                         sort.Add (loadSprites [index]);
                     }
                 }
 
                 tr = loadCards [i].GetComponent<Transform> ();
                 tr.position = new Vector2 (0, -3.45f);
                 tr.RotateAround (new Vector3 (0f, -12.57f, 0f), Vector3.forward, -36 + i * 8);
         }
 
         sort = sort.OrderBy (p => p.ToString ().Substring (2, 3)).ToList ();
         for (int i = 0; i < 10; i++) {
             sRend = loadCards [i].GetComponent<SpriteRenderer> ();
 
             sRend.sprite = sort [i];
         }
 
         sort.Clear ();
     }
 
     public override void OnStartLocalPlayer () {
         CmdSetPlayerID (string.Format("Player {0}", netId.Value));
         GenerateCards ();
     }
 
     public override void OnStartClient () {
         OnPlayerIDChanged (playerID);
     }
 
     [Command]
     void CmdAddUsedSprite (Sprite newSprite) {
         usedSprites.Add (newSprite.ToString());
     }
 
     [Command]
     void CmdSetPlayerID (string newID) {
         playerID = newID;
     }
 
     void OnPlayerIDChanged (string newValue) {
         playerID = newValue;
         name = playerID;
         if(isLocalPlayer) name += " Local";
     }
 }

This is the code i use to generate some playing cards in my multiplayer game, the generating of cards does work, the issue is the SyncListString usedSprites doesn't update across the server. I tried setting it up simmilar to playerID system which works fine but it doesn't seem to work. also I couldn't find any clear usage instructions online. Or if this is the incorrect way to transfer lists between clients across network could you point me in the right direction.