Keep in mind that I wrote this over 15 years ago! :D  (when I was reading perhaps too much Kenneth  Grant at the time lol)

There has been quite a bit of discussion on the 'nightside' of Enochian recently, or perhaps I just talk to those sorts ;) In Dee & Kelly's writings, as well as those of the Golden Dawn I have not seen any referance to working with the cacodemons or god names reversed. They were obviously included for a reason. Perhaps the darker aspects of Enochian are something that the practitioner should happen upon themselves, or at least that may have been the undrstanding. However, with the growth of the population's understanding of the fact that the 'nightside' energies can be worked with instead of feared, I think it is time to bring this to an open forum for discussion and growth.
I do not think that I have to go into what I mean by 'nightside', I am borrowing that term from Kenneth Grant. There is not really a seperation of forces, eg. nightside/dayside in the metaphysical world, however they are great terms for describing the energies of the cacodemons etc. in my opinion. I am personally reffering to 'nightside' in the sense of the 'darker' or more 'adverse' energies that are found when working with the enochian cacodemons. They are all part of the whole, however I do find an energy difference between them and say mordialhctga.
There is both a 'nightside' and 'dayside' aspect of all magick and the universe. It is how we as humans break down the universal energies, into opposites. Also within ourselves we can see the 'nightside' and 'dayside' energies. Why would Enochian be any different? I have only recently started on these workings, but still would like to share my ideas and experiences.

Eathyres
As far as the eathyres are concerned, I have found many different energies and experiences within. I have purposefully not read about anyone elses experience with the eathyres as I am still working through them, and do not want my experiences coloured in any way. (I personally tend to find that if I read about what 'should' be there, that is what I see). I have found their to be 'nightside' energies contained within the eathyres. Makes sense really, otherwise they would sort of be a one-sided experience. From skrying and experience travelling the eathyres, I do not see the 'nightside' aspect the same as that of the tree of life, a sort of inverted tree, or the backside of the tree. I experience the nightside energies within the eathyres within the dayside energy. It feels as though the energy is bieng turned inside out. I find one within the other. I'm sure that everyone experiences these energies within the eathyres differntly, this is just how I experience it. I originally started with the notion that perhaps their are 'inverted' eathyres, I found this not to be the case for myself. When I first decided to embark along the path of discovering the nightside energies to the eathyres I did some skrying with the enochian angels to get more information. I was repeatedly told "not to do it" at first. That "this is not a place for humans". I am not entirely sure whey they were so against the idea, however soon after that my life turned very chaotic, and I soon discovered that I was not ready for this path yet.
I have sinced worked (slowely) with this idea and found much success. I have also found that the enochian angels (at least to me) do not want to talk about this aspect much, and that the 'nightside' enochian biengs tend to not like humans.