[tex-live] Per user texmf.cnf

[Joseph Wright]

Hello all,

I'm trying to tackle a question on TeX-sx:
http://tex.stackexchange.com/questions/66614/change-texmfhome-per-user.
This is about moving TEXMFHOME, but seems to require a per user
TEXMFCONFIG. I couldn't seem to get this to work, so would value some
advice. On my Mac, I get

  palladium:~ joseph$ kpsewhich --var-value TEXMFCONFIG
  /Users/joseph/Library/texlive/2012/texmf-config

so tried creating a texmf.cnf file there containing a line to move
TEXMFHOME.

 TEXMFHOME = ~/texmf

but

  kpsewhich --var-value TEXMFHOME

showed no change (~/Library/texmf).

A quick search finds
http://people.debian.org/~preining/TeX/TeX-on-Debian/ch2.html#s-sec-user-config-files,
but I did not follow this really: as TEXMFCONFIG points to a
perfectly-valid location, why does it not lead to texmf.cnf being found?
Are there any general instructions for using texmf.cnf on a per user basis?
--
Joseph Wright