I think you missed it. Do my illustrations not show that the firmament includes BOTH the atmosphere (where the birds fly -- 1st heaven) AND that place where God placed the luminaries (2nd heaven)? Read Genesis 1:6-8, 14-18 very carefully.
Ah yes. Now I see. Thank you for the clarification. I agree with what your illustration shows in that post, however I should clarify how I interpret the 'Waters', beginning with this verse...
Psalms 148:4
"Praise him, ye heavens of heavens, and ye waters that be above the heavens."
The word 'Waters' has various meanings depending on the verse and context...
Strong's Hebrew: 4325. מָ֫יִם (mayim) -- waters, water (biblehub.com)
Here is an example of how that word is used in Genesis 1:2...
Genesis 1:2 (New American Bible)
"and the earth was without form or shape, with darkness over the abyss and a mighty wind sweeping over the waters"
In the translation above, Mayim is translated as 'Abyss', as in the 'Underworld'.
In the Bible, the abyss is an unfathomably deep or boundless place. The term comes from the Greek word abyssos, meaning bottomless, unfathomable, boundless.
Abyss (religion) - Wikipedia
Thus, the Waters are not physical oceans, or anything made of H20.
The point I am making is that in the two verses I quoted, the word 'Waters' should be understood to mean
Dimensional Barriers.
If we were to simply believe Genesis 1:2 in its most literal sense, then 'without form' means two-dimensional. Void means a complete vacuum. In other words,
the Third Dimension had not even been created yet. Thus, our Universe (Firmament) had not been created yet.
I believe a more accurate interpretation of Genesis 1:1 would be...
"In the beginning, God created Heaven and Hell."
If Earth is 'without form and void', then technically that is Hell, the Underworld, Sheol, etc. Even Jerimiah 4:23 seems to describe a 'Hellish' landscape in a state of 'Supernatural Chaos'.
This brings us to...
Genesis 1:6-8, "And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters. And God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament: and it was so. And God called the firmament Heaven. And the evening and the morning were the second day."
The above verses show God splitting the two-dimensional Abyss (boundless potential) and giving it physical depth (bound potential). In other words, the Waters under the Firmament is the dimensional boundary between 2D and 3D. The Waters above the Firmament is the dimensional boundary between 3D and 4D.
Something like this in your diagram...
Our Universe, the Firmament, exists in between the two Waters. Thus, with the creation of 3D Space, God can now place the rest of the components within it...
Genesis 1:14-18, "And God said, Let there be lights in the firmament of the heaven to divide the day from the night; and let them be for signs, and for seasons, and for days, and years: And let them be for lights in the firmament of the heaven to give light upon the earth: and it was so. And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also. And God set them in the firmament of the heaven to give light upon the earth, And to rule over the day and over the night, and to divide the light from the darkness: and God saw that it was good."
That is how I interpret it. Moreover, even the most advanced theories of Science are in agreement...
The WorldSheet was the 2D 'face of the Waters' that was then split apart and separated to create the World Volume 'Firmament' in between.