3rd player orientation using gyro with offset

Hi, I would like to control the orientation of my player with the gyro. I would also like to be able to add an offset (at the start with the compass true heading, and manually during the game with a finger swip, to correct the eventual drift of the gyro). My code is almost working but I got some problem that I can't resolve, I tried with Quaternion but it was a big fail as I'm still not very comfortable with it.

Thank you for advices

 #pragma strict
     
     import UnityEngine.UI;
         
         static var playerGPS: GameObject;
         static var gyroBool : boolean;
         private var gyro : Gyroscope;
         public var touchRotatesHeading : boolean = true;
         private var screenSize : Vector2;
         private var mouseStartPoint: Vector2;
         private var headingAtTouchStart : float = 0;
         var locationStatus:LocationServiceStatus;
         static var initCompass: boolean=false;
         static var refreshCompass: boolean=false;
       
         private var heading : float = 0;
         private var headingoffset : float = 0;
       
       
         
         
        function Awake() {
                         
             gyroBool = SystemInfo.supportsGyroscope;
                 
             if (gyroBool) {
                 
                 gyro = Input.gyro;
                 gyro.enabled = true;
                          
                 Screen.sleepTimeout = SleepTimeout.NeverSleep;
             } else {
                 #if UNITY_EDITOR
                     //print("NO GYRO");
                 #endif
             }
         }
       function Start() {
             screenSize.x = Screen.width;
             screenSize.y = Screen.height;
          
              Input.compass.enabled=true;
            
             WaitInitialisation();
             headingoffset=0;
             
         }   
         
        function FixedUpdate () {
                   
                   
             if(initCompass==true)
              {         
                  playerGPS=GameObject.Find("JAV_model_ete2015(Clone)");
                  heading=Input.compass.trueHeading;
                  headingoffset=heading-gyro.attitude.eulerAngles.x;
                  playerGPS.transform.eulerAngles = Vector3(0,heading,0);
                  initCompass=false;
                 
              }
              GetTouchMouseInput();
              
              if(Input.GetMouseButton(0)==true){
                    playerGPS.transform.eulerAngles = Vector3(0,heading,0);
                    }
                else if(Input.GetMouseButtonUp(0)==true)
                    headingoffset=heading-gyro.attitude.eulerAngles.x;
                    
                      
              else if(Input.GetMouseButton(0)==false){
                   
                    
             if(0<gyro.attitude.eulerAngles.y&&gyro.attitude.eulerAngles.y<=180){
             heading=gyro.attitude.eulerAngles.x+headingoffset;
             heading = heading%360;
             playerGPS.transform.eulerAngles = Vector3(0,heading,0);
             }
     
             else if(180<gyro.attitude.eulerAngles.y&&gyro.attitude.eulerAngles.y<=360){
               heading=gyro.attitude.eulerAngles.x-headingoffset;
               heading = heading%360;
               playerGPS.transform.eulerAngles = Vector3(0,180-heading,0);
          
               }
               }
             
         }
        
         
         
     function GetTouchMouseInput() {
             if(Input.GetMouseButtonDown(0)) {
                 
                 mouseStartPoint = Input.mousePosition;
                 headingAtTouchStart = heading;
                 
             } else if (Input.GetMouseButton(0)) {
                 var delta : Vector2;
                 var mousePos = Input.mousePosition;
                 delta.x = (mousePos.x - mouseStartPoint.x)/screenSize.x;
                 delta.y = (mousePos.y - mouseStartPoint.y)/screenSize.y;
                 heading = (headingAtTouchStart+delta.x*100);
                 heading = heading%360;
                 
                
             }
         }
        
       function WaitInitialisation() {  
           yield WaitForSeconds(5);
           initCompass=true;
       
       }