iOS - อยากทราบวิธีการที่ทำการเปลี่ยน Storyboards IOS หน่อยครับผมออกแบบไว้ 2 อันคือ iPhone 4 กับ 5

-(void)StoryboardSizeScreen
{
    UIStoryboard *storyboard = nil;
    if ([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPhone)
    {    // The iOS device = iPhone or iPod Touch
        CGSize iOSDeviceScreenSize = [[UIScreen mainScreen] bounds].size;
        if (iOSDeviceScreenSize.height == 480)
        {   // iPhone 3GS, 4, and 4S and iPod Touch 3rd and 4th generation: 3.5 inch screen (diagonally measured)
            NSLog(@"Support 3.5 inch");
            // Instantiate a new storyboard object using the storyboard file named MainStoryboard_iPhone
            storyboard = [UIStoryboard storyboardWithName:@"Storyboardiphone4" bundle:nil];
        }
        if (iOSDeviceScreenSize.height == 568)
        {   // iPhone 5 and iPod Touch 5th generation: 4 inch screen (diagonally measured)
            NSLog(@"Support 4 inch");
            // Instantiate a new storyboard object using the storyboard file named Storyboard_iPhone4
            storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard-iphone" bundle:nil];
        }
    }
    else if ([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPad)
    {
        // The iOS device = iPad
        NSLog(@"Support ipad ");
        // Instantiate a new storyboard object using the storyboard file named Storyboard_iPhone35
        storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard-ipad" bundle:nil];
    }
    // Instantiate the initial view controller object from the storyboard
    UIViewController *initialViewController = [storyboard instantiateInitialViewController];
    
    // Instantiate a UIWindow object and initialize it with the screen size of the iOS device
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    
    // Set the initial view controller to be the root view controller of the window object
    self.window.rootViewController  = initialViewController;
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    [self StoryboardSizeScreen];
    [window makeKeyAndVisible];
    return YES;
}