I think that people overstate the affect of wiring configuration versus battery balancing. Absolutes like you will charge one and discharge another are just incorrect. The wiring configuration is a second order affect. Yes it has some affect but it's not a major affect unless the wire size is very small.
Generally the internal resistance of the batteries is higher then the wiring resistance. This tends to balance things.
Here's a web site that talks about the internal resistance of lead acid batteries:
http://www.physicsforums.com/showthread.php?t=634808
And another site the has a table for the resistance per foot of various sized wire.
http://en.wikipedia.org/wiki/American_wire_gauge
I'm not saying to ignore wiring configuration, just keep it in perspective - it's a second order thing.