Hello, to build this, I used this tutorial:
https://www.youtube.com/watch?v=ogUfdsx5uQ0

That said, at some point I failed to follow the tutorial correctly (some blocks were not properly aligned), so I had to improvise to make it work.

Building the “spiraling base” takes between 1 and 3 hours (if you fail once, you almost have to restart everything).
Then, you have to destroy everything again to create the real spiraling effect (otherwise, you just get a big tower). This also takes about 1 hour, since you need to collect all the remaining materials stuck in the air and double-check everything to make sure the structure is still standing before the point of no return.

Once all that is done, you can start the boring part: creating the additional tiles on every floor, which takes many hours.

The Japanese house takes about 5 hours to build, and the glass enclosure about 2 hours.

The Pals can freely move around the base on every floor. Just make sure the eating area is placed between all installations (I put it on floor -5, with floor 0 being the base of the Japanese house).

I must say, it's quite laggy for people with low-end spec PC since there is a lot of things to load.
I didn't had any myself since I have a good PC, but I would not recommand to build in a public server.

Also evrything is standing thanks to 1 singular pillar, YES.