Set Windows Wallpaper Stretch Method for UWP?

[RoboLam]

So setting the wallpaper is pretty trivial for UWP apps

await Windows.System.UserProfile.UserProfilePersonalizationSettings.Current.TrySetWallpaperImageAsync(file);

However this method always defaults to "Fill" mode. Does anyone know of a way to either change this default or change the setting after calling TrySetWallpaperImageAsync()?

Thanks in advance!