Overanalysis is Magic: Just how large are the Canterlot Archives in the Your Human And You-verse?

>>Be me
>>Be re-reading Chapter 33 of Your Human and You by MadMaxtheBlack

“Over two million books,” Twilight spoke up from beside me. I glanced over at her and saw her staring out upon the sea of bookshelves in front, above, and below us with a dreamy expression on her face. Sighing happily, she turned to look at me, giving me a large smile, “Welcome to the Archives.”

Over two million books, huh? Well, let's see if Twilight's numbers add up.

Beware, stranger, there be Math. Also there be the Metric system. No spoilers though.

Are you still here, my friend? Very well, in this case let us continue on, shall we?

First and foremost, allow me to lay down some ground rules. Simplifications, or assumptions, if I may.

Each shelf was packed full of scrolls, books, tomes, journals, and other countless pieces of information.

Let us assume, for simplicity, that every piece of information to be a "book" one or more pages thick. This assumption allows us to perceive the shelves as filled only with books, albeit of varying sizes. With that simple but important trick taken care of, we may carry on.

Speaking of shelves, we happen to have their exact measurements:

Each of the surrounding bookshelves were at least twelve feet high, the tops of them disappearing into the darkness above us.
...
Each of those three shelves were twelve feet high, and if they were anything like the other shelves we passed, were three hundred feet long as well.

As we all can see, each shelf is 300 feet long and 12 feet high, or
91.44 m X 3.66 m

Now we know how large is a shelf, but how many shelves are there in the Archives? Thankfully, the text gives us several hints to that as well:

When we reached the end of the aisle, Twilight stopped again. Motioning with her hoof, she indicated the shelves just in front of us, “These three shelves hold all the information we have on humans.
...
The railing we had reached wrapped around a massive hole in the floor, nearly fifty feet in diameter. A set of double spiral staircases emerged from the hole, rising into the air to another hole in the ceiling. Surrounding the hole on all sides were more bookshelves, which ran away from the hole like rays from the sun.

I believe it's high time that I introduce you to my old friend Lower Bound. No, that's not the name of my kinky OC, but rather a delightfully useful mathematical tool. A lower bound is an element of an ordered set that defines a subset of elements that are less or equal to it.
For example, a lower bound of a subset of numbers from one to five in a set of numbers from one to infinity would be five... Got it all down? Good. This will be on the exam next week.

Now, back to business. Before our little lecture on Order Theory we were discussing the shelves, namely their quantity and location. And we have unraveled several fascinating facts that enable us to set lower boundaries.
For instance, the mention of "these three shelves". Keeping in mind that the shelves were encountered by the characters after they "reached the end of the aisle". This fact leads us to assume that the lower bound — the possible minimum — for the number of shelves in a line is at least 3+1, or, you guessed it,
4 shelves in each line.

Now, according to the text, the shelves "ran away from the hole like rays from the sun". After a careful inspection of the third best Princess' butt I can confirm that the Sun has exactly eight rays, so we're rolling with that. If you happen to disagree, feel free to kiss the source of the data.

This conclusion awards us with the lower bound for the number of shelves on a floor, which is
4 * 8 = 32 shelves on each floor.

What's left is to determine how many floors are there.

My eyes widened as I saw that there were several more floors beneath us, each filled with shelves of books. After three floors, the stairs disappeared into the darkness, Twilight’s light no longer able to illuminate the depth of the room. Glancing up, I saw the exact same thing applied to the ceiling as well; the spiraling staircase rising several floors up before disappearing into darkness.
...
“We’re on the fifth floor,” Twilight said simply before turning and heading towards the stairs.

We can see three floors below and three floors above, and we know that we are on the fifth floor. It doesn't take a genius to deduct that there are at least 8 floors to the building. Unless you are a Brit (or a Hawaiian, for that matter), in which case add the ground floor.
Disregarding the latter clarification, this brings us to a total of
32 * 8 = 256 shelves in the building (assuming all the floors are similarly designed).

Here comes the time when we can not move forwards without one more assumption. Two, in fact. While we have declared the thickness of a generic book as a variable, we are still to determine its format. I will take a wild guess and go with Quarto (12 inches / 30 cm high) as one of the oldest formats out there, as well as assume the thickness of each shelf board to be a generous 4 cm (1.75 inches) thick — the shelves are long and filled with books, the wood has to be strong to support all the weight, right?

With that said, one vertical row of books in a shelf will hold
3.66 m / (30*4) cm ~= 11 books on one side, or 22 on both.

Assuming that the books are soft-covers, and assuming the page paper to be of density of 115 g / m^2 (0.09 mm / 0,00354 inches thick), the number of pages in an average book in the Archives would be the X in following equation:

2 000 000 [number of books] = 9144 cm [shelf length] * 256 [number of shelves] * 22 [number of books per vertical row] / 0.009 cm [thickness of one page] / X [number of pages in a book] =>
X [number of pages in a book] = 9144 cm [shelf length] * 256 [number of shelves] * 22 [number of books per vertical row] / 0.009 cm [thickness of one page] / 2 000 000 [number of books] =>
X = 9144 * 256 * 22 / 0.009 /2 000 000 = 2861

2861 pages in an average book.

I call shenanigans.

Buuuut that's just a theory. A-Your-Human-and-You-verse theory!
Thanks for reading!

PS.
Feel free to disprove me in the comments.
PSS.
Yes, this is my idea of "fun".
PSSS.
Yes. Twilight is the best pony.