Finally taking the LiPo leap.

[suicideneil]

Yes, but...

The adapter board you linked to seems to be for purely balancing two packs in parallel, not for normal balance-charging. What you need to make, or find, is slightly different:

http://www.scriptasylum.com/rc_speed/_lipo.html

scroll down to the bottom section, and select '2s + 2s' option- you will see the balancer harness has been tweaked so that the charger sees a 4 cell pack, rather than 2x 2s packs in parallel (same too with the main power leads).