The Kanji at the top right read "The Void". The Kanji on the bottom right read ("the thickness of a single piece of paper"). The Kanji in the right side of the diagram read "Emptiness" and "Matter" (i.e. "Heaven" and "Earth"). In the center is the single Katakana character "Yu", which in Kotodama terms stands for the harmony of Fire and Water (i.e. "In" and "Yo").
Interesting stuff. FWIW, the "ichi-rei etc." formulation is found in some Shinto lines other than Oomoto (sorry, no references at hand -- later). For my money, what was original about Deguchi's presentation was the particular mix and dramatic presentation of a wide range of elements gathered from earlier traditions, rather than any particular innovation specific to Oomoto.
The comparison of the drawings near the close is particularly suggestive. I don't want to quibble, and perhaps my eyes aren't as reliable as they once were, but that single Katakana character in the center looks to me as if it is "Su" and not "Yu." But I'm not sure this possible variance has much effect on the totality of your presentation.