By nicer I don't necessarily mean making this public, but I think we should think about what the most helpful scenarios and make sure we have specific extension methods for those, e.g. (hypothetically) in addition to SetupConfigOptions and SetupOptions we could have SetDefaultOptions or something in those lines. I wish we can avoid exposing the ability to do custom ordering, but if we can't I think a public enum can be better than taking a an int, because users can at least do things like services.SetupOption(..., order: OptionsOrder.Configuration + 1).