How would you compare the experience of Gentoo / Arch vs LFS? I used to do a lot of Gentoo back in the day, and nowadays occasionally Arch, and while I believe it lead me to have a very solid foundation of a lot the system, especially the kernel bootstrapping process is a bit of a gray area to me (how do initial ramdisks fit in the picture for example).

Is my understanding correct that these are the things that you definitely have to work through with LFS?