How do you convert a UUserWidget to a SWidget? Needed for a loadingscreen.

I'm curious what you did to get it working with your UMG widgets. I attempted to essentially get a UUserWidget to the SWidget needed and when debugging it has a valid object. However I then receive a Rendering Thread exception. It works with the base load screen from FLoadingScreenAttributes::NewTestLoadingScreenWidget(). The relevant part of my Game instance is below. the wLoading essentially is where the LoadingWidget is set and then it constantly gets casted or built into an SWidget to be placed inside the movie player loading screen.

   UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Widgets")
     TSubclassOf<class UUserWidget> wLoading;
 
   UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Widgets")
   UUserWidget* LoadingWidget;
 
 private:
   TSharedPtr < class SWidget > loadswidget;
 
 
 void UCustomGameInstance::Init()
 {
   UGameInstance::Init();
 
   FCoreUObjectDelegates::PreLoadMap.AddUObject(this, &UCustomGameInstance::BeginLoadingScreen);
 
   FCoreUObjectDelegates::PostLoadMap.AddUObject(this, &UCustomGameInstance::EndLoadingScreen);
 
   LoadingWidget = CreateWidget(this, wLoading);
   loadswidget = LoadingWidget->TakeWidget();
 }
 
 void UCustomGameInstance::BeginLoadingScreen(const FString& MapName)
 {
     FLoadingScreenAttributes LoadingScreen;
 
     LoadingScreen.bAutoCompleteWhenLoadingCompletes = true;
     LoadingScreen.WidgetLoadingScreen = loadswidget;
 
     GetMoviePlayer()->SetupLoadingScreen(LoadingScreen);
 
 
 }