GUI text & button getting small in iPad Air

I have developed a project in Unity & the whole project is developed using GUIs only. This is a complete project. I uploaded an iOS build of this on the App store. But Apple rejected this build due an issue which is only found on the iPad Air. In one of scenes the texts in the GUI labels are becoming very small to be visible. The code that I am using is as followed.

 function OnGUI()
 {
   screenWidth = Screen.width;
   screenHeight = Screen.height;
   
   
         if(screenWidth > screenHeight){
                yRatio = (screenHeight / 1536);
                instructionHeaderStyle.fontSize = (100 * yRatio);
                guiSkin.label.fontSize = (80 * yRatio);
         }else{
                yRatio = (screenHeight /2048 );
                instructionHeaderStyle.fontSize = (75 * yRatio);
                guiSkin.label.fontSize = (48 * yRatio);
         }
         
         GUI.skin = guiSkin;
   
   GUI.DrawTexture(Rect(0, 0, screenWidth, screenHeight), helpScreenBgTexture);
   
   GUI.Label(new Rect((screenWidth -screenWidth* 0.3)/2 ,screenHeight * 0.30,screenWidth *0.3,screenHeight*0.1),"INSTRUCTIONS",instructionHeaderStyle);
   
   var helpText:String = "Some Text";
 
 }

The texts given in the above code are quite bigger to be visible in the iPad1, iPad Mini & iPad 2. But it's not the same in the iPad Air.

I really need some serious help here. Every help is hugely appreciated.