I did stage 0 installs a few times. While it took a long time, there was fairly little work on my side. Most of the grunt stuff had been automated.[0] I think the only thing the user had to do was config.

[0] Which is the point of Gentoo, after all. It's what made it a lot better than LFS/BFS. You get everything from source with little effort. 17 years later, I'm still using Gentoo. Nothing like it.