Could you clarify how you arrived at 84% battery health? After the command "ioreg -l -n AppleSmartBattery -r" I see DesignCapacity, but where does the other number (5629) come from? I'd like to compute battery health myself...
Coconut Battery is nice. You can let it take snapshots and compare it with other batteries online. You can view my battery health here http://ccbonline.coconut-flavour.com/index.php?bid=d78a6c124.... I try to unplug at 100% and recharge it at 10-20%. Once per month I drain it all the way to 0%.
After reading this thread I try to keep my battery at a 50-80% charge :)
Except when I do some CPU intensive stuff like compiling or rendering, then it is being charged thought the process.