Vr hand rotation tracking,Vr hand tracking

I have been trying for the past couple of hours to take a value of the current rotation of the players left hand and subtract it from the past one and then add it to an array or list.

 public SteamVR_Action_Skeleton leftSkeletonAction = null;
 public SteamVR_Action_Skeleton rightSkeletonAction = null;
 public SteamVR_Action_Boolean leftTrigger = null;
 // Left Hand
 public GameObject leftHand;
 public float leftThumbCurl;
 public float leftIndexCurl;
 public float leftMiddleCurl;
 public float leftRingCurl;
 public float leftPinkyCurl;
 public Vector3 leftHandRotation;
 
  

 // Start is called before the first frame update
 void Start()
 {

 }

 // Update is called once per frame
 void Update()
 {
     // GET FINGERMOVEMENT AND TRACKING

     // LEFTHAND
     leftThumbCurl = leftSkeletonAction.thumbCurl;
     leftIndexCurl = leftSkeletonAction.indexCurl;
     leftMiddleCurl = leftSkeletonAction.middleCurl;
     leftRingCurl = leftSkeletonAction.ringCurl;
     leftPinkyCurl = leftSkeletonAction.pinkyCurl;

     // LEFTHAND TRACKING
     leftHandRotation = UnityEditor.TransformUtils.GetInspectorRotation(leftHand.transform);
   

     
     if (leftTrigger.state)
     {

         RecordLeftControlerMovement();

     }


 }

THE THING DOWN HERE

 public Vector3[] numberArray;
 public List<Vector3> finalList = new List<Vector3>();
 public Vector3 firstVector3;
 public Vector3 secoundVector3;
 
 public void RecordLeftControlerMovement()
 {
     
    
         numberArray = new Vector3[2];

         numberArray[1] = leftHandRotation;

         firstVector3 = numberArray[1];


         
            
         numberArray[1] = leftHandRotation;

         secoundVector3 = numberArray[1];

         finalList.Add(firstVector3 - secoundVector3);

             

             
 }
   
 

}

it just adds a 0 to the list so i'm wondering if i just need to slow it down or am i taking the wrong approach to this.