I commend you on how well done and clear your video is, and I really like the hardware cloth "lid" you put on there. It's a neat, clean looking brooder. I have the same concerns as everyone has already expressed, but then as my friends @PD-Riverman and @dhelzel know, I don't ever use heat lamps for chicks and I brood them directly outside where they'll be living for the rest of their lives. That's simply my choice. It seems to me that 100 degrees anywhere in the brooder is simply too too high. They might be doing okay now, but in your measurements you didn't take into account their own body heat being given off, heat radiating off the water, the water container and the feeder, and their activity level. Water absorbed into the wood and the bedding is going to raise humidity in there as well. It also doesn't seem to me that they have any respite from the glare of the light itself - no darker little area where they can have a few minutes out of that spotlight.
But one of the things that caught my eye was in the first post where you said it would hold "a bunch of chicks" and then further down in another post you said that they have a 3 foot circle. Um, I'm not the brightest crayon in the box, and math is not my strong suit, so while I know how to find the square footage of a rectangle or square, I don't know how to find the area of a circle. I can tell you that by the time a feeder and a waterer are in there and you have chicks added to the mix, they will be out of adequate space yesterday.
I think there's a simple solution to those issues without scrapping your entire brooder, which looks great, by the way. How about putting another box, same basic configuration, off to one side and connected with a little opening? They could get away from the heat and brightness, you could put the food and water in the "dining room" which would keep those at a nicer temperature, and still give them a lot more space.
It's so hard, when you know that someone has put so much effort into something, to say, "Wait, I think there are some problems." And it's even harder to be the one who put in all the hard work and shared it only to feel like folks don't like it. It's not a matter of "not liking" it....I just think that the key here that none of us want chicks that survive, we want chicks that thrive. So I hope you take what we're saying in the spirit it was intended.