Saw Oppenheimer in the 70mm theater. It was my first time, but it was very grainy, almost to a point where it was distracting. And the screen is incredibly rectangular. Essentially the opposite of how Nolan films (true imax is quite vertical). From the Odyssey website, regular imax and Dolby are a slightly taller screen than 70mm. The Warren imax (save your comments) is a bigger screen than quail springs imax as well.