Your total deck size must still be 100 cards, so if you are using Partner to play with two commanders, the rest of your deck must contain 98 cards
Its not guaranteed to win you the game but forces your opponent to be more creative in how they proceed
In each of these cases, the modes must be equal in power because of the shared cost
(Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.) When this creature enters, draw three cards, then put two cards from your hand on top of your library in any order
That being said, if I had to pick the two strongest Elder Dragons from the cycle, my choices would be Witherbloom, the Balancer and Prismari, the Inspiration
If Standard Procedure is no longer in your hand at that time, it won't become the chosen card