I may be wrong, but I have some of the West systems that is suggested for such a job, and it becomes a multi pour. What I have had to do is turn your ring on it's side, and put a smooth flat surface like a piece of plastic/glass under the outside hole, and fill it in from the inside hole. I  can fill the pour all the way, but at best only get 2 holes filled per pour, lest it just flow out the open side. Once hardened, roll to the side and repeat.