Gentoo mirrors in installation documentation

[Leon]

I was installing gentoo on my workstation. When emerging the system
I found that downloading files whas rather slow, the ibiblio.org server reached a max. download of 30KB/sec.

I knew there is a "GENTOO_MIRRORS=" variable in /etc/make.conf but it wasn't present or documented in the 1.4 17-01-2003 iso I was using.

I manualy added GENTOO_MIRRORS="http://ftp.snt.utwente.nl/pub/os/linux/gentoo/ http://www.ibiblio.org/pub/Linux/distributions/gentoo" and I pulled my maximum download of ~400KB/sec, A +10x increase.

I was wondering why this isn't mentioned in the installation documents?

(If this is the wrong forum I apologize)