But why is vertex order important? It seems like there might be better ways to do what you are really trying to do.
Be careful not to be a victim of the “inject things into my stomach” syndrome.
Maybe it really is critical to have a specific vertex order but it comes up so rarely (never?) that it’s worth looking into why it’s important to you and if there is a better way to achieve the final results. Relying on it certainly seems very fragile.