Ah yes, Sheikh Al-Akbar, The Greatest Sheikh, Ibn Al-Arabi, is definitely, I think, potentially a very fruitful area of investigation if we are going to speak of, as you say, "Worlds that exist and yet are non-manifest." Henry Corbin's book, Alone With The Alone: Creative Imagination in the Sufism of Ibn 'Arabi, and some his other books,(not to mention Arabi's own writings themselves), contain some very interesting and in depth looks at some of these "intermediary worlds" , as I'm sure Bruce is well aware, but some of the readers might not be.
Also, I think you're right on here when you mention Rumi, and the importance of "the heart as the most developed sensory organ whose vast abundance of embedded nerves, is second only to the mind itself." The Sufis call the heart an "organ of perception" , and with Science telling us that there is an abundance of neurons in the heart as well as the brain, maybe the Sufis are right. Of course, I could also point out, as many are probably already aware, that the Chinese word, Shin or Xin, and the Japanese word, Kokoro, both have the dual meaning of "heart-mind" , and that they're the words they use to refer to what we in the west just call "mind." But if you ask them where this "mind" is, they point to their chest, not their head like we Westerners do. And then, of course, this also calls to mind the Native Americans' heavy emphasis on speaking and acting "from the heart." They too, make a correlation between the heart and mind, as do many "tribal" traditions. I'm sure you can think of many other examples.
And in my research as well, as you say, "one provocative notation appears again and again" , that being, "the pre-existing emotional tenor of the experiencer." And this goes for any type of experience, from the "mystical" to the "supernatural" to the "paranormal" or what have you, emotions seem to play an important function in all this. As an example from Mysticism, we have the Sufi Dhikr Ceremony, in which music, chanting/singing, movements and dance, together with the overall environment, are all designed and used to bring the participants emotions and energy level to the highest pitch possible, and therefore, hopefully, ideally, launch the participant, the Dervish, into some heavy mystical experience, or some type of "altered state of consciousness." I'm sure the reader can think of examples from other traditions around the world where this technique is used.
Ah, but we should watch out, because, and I'm sure Bruce is well aware of this, as both Idries Shah and Gurdjieff tirelessly point out, emotions, or rather, mystical experiences connected with intense emotional states can be dangerous and decieving sometimes, if not most of the time. And if it can be dangerous and decieving for "mystical" experiences, then I imagine this would apply to any other type of "paranormal" or "supernatural" experiences. So I think we should definitely be aware of that factor.
And I agree that clinical-type research environments probably do have a "dampening effect" on the emotional angle in all this. And of course, as Bruce is well aware, environment is always an important aspect to consider in any experience, beit paranormal, mystical, or even just plain "normal".
As far as harmonics goes, being something of a musician myself, you'd think I might have something to say on the subject, but alas, I do not. Although I did find what you said, and the YouTube video, quite interesting and intriguing.
Anyway, that's all I have to say for now. Sorry if it was a bit long, but I wanted to try and contribute something to the discussion.
Peace to All