What is the smallest possible size of Nalimov endtables? I have recently found the following place, where I can find the outcome for any 6-piece endgame with Nalimov endtables.

I was surprised to see this, because I have recently read that set of tables requires 1153 GB of hard disk space. This is significant amount of space and also it is not so easy to search through it. But nonetheless this website can give you the result together with a mating series in &lt; 1 second.

My first guess is that they are not using all endtables. There is little point of searching the mate of lonely king VS 4 pieces. But at the very best it takes away 1/4 of all the size.

My vague question is: how can it be done? My normal question is: what is the smallest size of reasonable 6-pieces Nalimov endgametables (by reasonable I mean where the result is not obvious)? Also it would be nice if someone can tell where can I get this smallest size endtables.
You can get a smaller 6-piece tablebase here, fully compressed.

https://github.com/syzygy1/tb

While I have personally not tried that, I know because of a friend that they are really good. If you were hoping for smaller stuff, this is as small as you can get. After all, there are lost of positions with 6 pieces.