A little information on versions of "Inauguration of the Pleasure Dome": an early version, which seems never to have been distributed, had a sound track by Harry Partch. The 1954 version, which circulated widely, had Janacek's "Glagolithic Mass" for a sound track. A three-screen version was presented at the experimental film festival in Brussels in 1958 (but also never distributed, as far as I know). Then in 1966, Anger released the "Sacred Mushroom" version, which was supposed to be watched under the influence of psychodelic mushrooms or other drugs. It begins with a reading of Coleridge's "Kubla Kahn" and has a number of images added to the 1954 version, including photos of Aleister Crowley; also horror movie sound effects were added to the sound track. Later, I'm not sure when, Anger deleted the Janacek sound track and put music by the Electric Light Orchestra in its place. That is the the version included in the "Magick Lantern Cycle," which includes all of Anger's films from "Fireworks" to "Lucifer Rising."
You can find detailed readings of the film in P. Adams Sitney's Visionary Film and my Light Moving In Time: Studies in the Visual Aesthetics of Avant-Garde Film.