Regarding your question about the numbers of tall white children present at the Indian Springs base... The best I can do is to describe the number of children that I personally saw.
As described in my books, The Teacher had one daughter. When she came with the children there were at most three equivalent in age to human children in perhaps the second or third grade. They were her daughter and two little boys.
On the day that I describe in Book One, in the chapter entitled "Tumbleweeds" when I was playing "catch the wind" with the tumbleweeds that the children were throwing up into the wind, I saw The Teacher with somewhere between 12 and 20 children of all ages from grade school through high school out playing in the sunshine. Because of the distance, the heat waves and the changes in elevation due to the ridges out to the east of my Range Three Weather Shack, I couldn't get an accurate count.
On the morning described in Book Three in the chapter entitled "The End of the Innocence" when there were at least 200-300 Tall White adults lined up along the base of the mountains 1 - 1.25 miles east of me over by the ammunition bunker, there were, I estimate, 35 to 75 tall white children of all ages from grade school through high school spread out in the crowd.
(Along with somewhere between 35 & 75 scout craft parked out in the section of the desert that I named "The parking area.” Since the scout craft could hold anywhere from 5 to 20 individuals depending on the model, there could easily have been many more Tall Whites present than the low numbers that I estimate. There were so many Tall Whites and scout craft that I wasn't able to accurately count them all.)
On that morning, as you probably remember, I also describe seeing a small group of human USAF Generals, high-ranking officers, and 2 or 3 high-ranking U.S. Government officials in civilian clothes also standing in among the Tall Whites.
In Book Three, in the opening chapter entitled "Winter Roads," when I got a good solid look at the damaged side of the large deep space craft as it was sliding by me, I could see the faces of many children looking out the windows that were positioned along the middle row of windows and physically located near the back (undamaged) section of the craft. I estimate that there were perhaps 50-75 Tall White Children on board of all ages from grade school through high school.
On that occasion, I could also see a lone tall white woman sitting in among them. She was an older woman (their Teacher, I suppose), and she also was looking out at me. I shall always remember the emotional look on her face. It was one of intense relief. She couldn't have said "Thanks" in a more meaningful manner if she had said so with words. She had obviously been taken to her emotional limits protecting the children after the accident had happened.
Since the deep space craft usually arrived on schedule during sundown on the night of the full moon, the number of children at the base probably fluctuated somewhat.
The deep space craft came in three general sizes.
The largest size just barely made it through the hanger entrance.
The smallest size was about half the size of the largest.
The in-between size was about half-way in size between the smallest and the largest.
The number of deep space craft in the hanger varied from month to month. Some months I had no idea how many were at the base. Even on months when I paid careful attention, it was very easy for deep space craft to arrive and later leave (on the night of the new moon) without my seeing them. However, on some months I did personally see at least 1 large and 3 small craft in the hangar which I estimate is equivalent to 2.5 large craft.
From this I estimate that some months there could have easily been 2.5 times 75 = 200+ children of all ages on the base at any one time.
Although this number seems to me to be somewhat on the high side (some months I only saw 1 small craft arrive, which would translate into only 25-40 Tall White children of all ages) there were clearly enough facilities for that many children (200+) along with a corresponding number of adults.
Remember the different scout craft hangers and the main living quarters were underground and obviously had substantial capacity.