Eight inches in diameter! I thought mine were big at 4-5" in diameter.
Cheryl, you probably already know what I do with all my plumeria, so I won't repeat it here. But IF I had such a huge tree, I would be taking cuttings here and there and rooting those cuttings. You are not only insuring that you will have plants if something were to happen to the "Mother" plant but also relieving some of the stresses associated with growing such a huge plant in a pot.
Hetty is much more expert than I, so hopefully she will give you some direction.