Need reference doc on precedence/ordering for pg_hba.conf

In particular, something quite a bit more verbose than the offical docs
on www.postgresql.org/docs (which are good, but not quite detailed
enough for me to unravel which entry in one particular pg_hba.conf is
taking precedence, and how to add several new entries that won't break
anything else).  Every experiment I've tried has *almost* worked in the
manner I'm understanding from every bit of documentation I've found, but
something always breaks.  :(

Failing that, a diagnostic poke to the head to tell me where in this
config I should put entries that refer to both local socket connections
and remote TCP/IP connections for one specific database that I want MD5
(or crypt, for the old 6.x client :/  ) authentication on:

=========
# From Debian Sarge stock install
local   all         postgres       ident sameuser
local   all         all            ident sameuser

# Added for local software using PG
local   template1   all            ident
local   sameuser    all            md5
local   all         root           trust

# More entries from stock Debian package
host    all   all   127.0.0.1   255.255.255.255   ident sameuser
host    all   all   ::1  ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
ident sameuser
host    all   all   ::ffff:127.0.0.1/128         ident sameuser

# another local config - the real entry contains a real IP
host    all   all   [host IP]    255.255.255.255   trust

# Last stock entry
host    all   all   0.0.0.0      0.0.0.0           reject
=========

(Comments trimmed out, whitespace mostly compacted;  linewraps are not
present in the real file - but my new entries don't function as expected
when I put them where I *think* they should go.)

-kgd