I'll take a few notes here on the subject matter for possible further development later.
5D: 5th chakra, 5th sign Leo (Being, or Self-Awareness), and its opposite Aquarius (Knowledge, or Spherical Awareness);
The first four densities continuously recycle to and from 5D; 5D is maturity and all the beings from 1D to 4D are in a phase of maturation for reaching 5D finally. In 5D, each individual is completely aware of God as self; timeless, universal cocreator.
4D: 4th chakra, 4th sign Cancer (Love, Care), and its opposite Capricorn (Responsibility)
In STO terms, 4D is society as a real family or network acting with true solidarity. They are fully committed to love and help each other for gradual maturation to 5D; self as God, the infinite creator, which is of course the essential theme of 7D but 7D is not an invididual to do something. It is completely non-dualistic, no two separate things or concepts. It is perfectly pure being. I think this is closely related to the Cs statement, "Prime Creator Manifests IN you". 4D love helps individuals gradually become more and more confident and "courageous" to become aware of the "Leonine"/Godly reality.
3D: 3rd chakra, 3rd sign Gemini (Birth of Individual Awareness), and its opposite Sagittarius (Birth of Global/Spherical Awareness)
This is where we are. Fresh self-aware souls in the process of developing a basic understanding of what they are and what everything is all about, and the relationship between the two.
There are some fundamental similarities between 3D and 5D. Or rather, there appears to be some fundamental similarities of functioning among 1D, 3D and 5D on the one hand, and among 2D, 4D and 6D on the other.
There is an explanation in Ra that I consider to be relevant:
Questioner: Why are the red, yellow, and blue energy centers called primary centers? I think from the previous material I understand this, but is there some tracing of these primary colors back to intelligent infinity that is more profound than what you have given us?
Ra: I am Ra. We cannot say what may seem profound to an entity. The red, yellow, and blue rays are primary because they signify activity of a primary nature.
Red ray is the foundation; orange ray the movement towards yellow ray which is the ray of self-awareness and interaction. Green ray is the movement through various experiences of energy exchanges having to do with compassion and all-forgiving love to the primary blue ray which is the first ray of radiation of self regardless of any actions from another.
The green-ray entity is ineffectual in the face of blockage from other-selves. The blue-ray entity is a co-Creator. This may perhaps simply be a restatement of previous activity, but if you consider the function of the Logos as representative of the Infinite Creator in effectuating the knowing of the Creator by the Creator you may perhaps see the steps by which this may be accomplished.
I think that the second or opposite sign in each polarity of signs signifies a more global understanding (including others) of what is learned through the representation of the first sign. This is actually symbolized by the second sign of the first polarity of Aries and Libra (1D). As it is a very basic understanding in astrology, Aries is about "self" and Libra is about "others", so in all the subsequent/higher polarities, the first sign is more about the self while the second is more about others. For instance, around the first (Geminian) half of 3D, focus of interest is very much on self while in the second (Sagittarian) half, conscious consideration of other selves and/or of the relationship between the self and other selves is much more emphasized. This is not only about the difference between self and others but also about the difference between local and global.
By the way, just like some basic functions of lower densities (1D and 2D) are reflected in the 3D, probably the same also applies for higher densities, so they are also reflected in 3D, and others. 4D lessons of love and responsibility are so significant in 3D. So the first half of 3D is more about love or care of "self" while the second half is more about loving or caring for "others", which is associated with more responsibility taking. And in terms of 3D reflections of 5D lessons, similarly, the first half is more focused on self-awareness as in, "I'm God" singularly, while the second half brings a significant recognition of "Other Gods". As for 6D, represented by the polarity of Virgo and Pisces, which is very much about serving, I think that this is reflected in 3D as serving more for one's own specific family/clan/circle in the first half and then serving more generally or indiscriminately.
So, the first halves of each polarity of densities are more focused on "self" while the second halves are more focused on "others" and I think this is very much about the maturation/growth from the first to the second halves. It appears that "Service to Self" orientation is somewhat stuck in the first half (the "self" half) all the times in connection with a corruption based on free will somehow. It is probably always natural for souls in the first half of any density to be relatively more self-centered because this is something like childhood, you grow and gradually lessen your self-centeredness and taking gradually more responsibility for others. But somehow the focus of awareness for beings committing to STS is stuck on self, regardless of whether they are in the first or the second half of any density. This seems to be related to the Cs explanation, "STO flows outward and touches all including point of origin, STS flows inward and touches only origin point."