I don't have any experience in this department, I mean the one with making your own, but I'll leave you some useful sources. On the other hand, I did have an above ground pool at my old house, couldn't relocate it when I moved cause there's no backyard space here so I sold it to some friends. I was very happy with it, it was a Coleman, did its job, never had problems with it, even installed a system to have saltwater. Fun for all, no comment here. It was a bit annoying when I had to clean it, but that goes for all pools, so I can't really complain about that either. And yes, it takes just a few hours to set it up, depending on its size, you might even be able to do it with just another person not have to call in all of your friends. If I were you, I'd definitely go for buying an above ground kit, but maybe you're more skilled in the DIY department and who knows, can do an in-ground on your own.
https://www.optimainstitute.com/pool/above-ground-kits.html
https://www.fixr.com/comparisons/in-ground-vs-above-ground-pool
https://www.popularmechanics.com/home/outdoor-projects/how-to/a3482/4276117/#
https://www.diyncrafts.com/39229/home/6-simple-diy-inground-swimming-pool-ideas-that-will-save-you-thousands

I know I'm a bit late on the topic, but it seemed pointless to start a new thread on the same discussion. I read this post and https://popular.reviews/best-portable-air-compressor/ the MAX2400 initially was the model I was going to buy, but then I switched for the Porter-Cable C2002-WK cause it was a bit cheaper, more within my budget. I am pretty pleased with my acquisition, don't get me wrong, but I was wondering whether you ended up buying the Makita MAX2400 or not and if you are pleased with the pressure and overall performance, if you can give me some intel a bit. I want to buy an air compressor for my father and now money allows me to get the Makita, I wouldn't want to cheap out.

Still, how do you think the light will get in? Maybe I'm missing something, but it doesn't seem feasible at all.

Yes, it does help. Do it whenever you see it is needed.

Wow, really nice work there bud. Keep us posted on how it all evolves.