I just went through this for a client using Resource Pools as logical containers(Big No-No IMO). I break it down to 3 pools Dev Test and Prod and use Andrew Mitchell's script to re-balance custom weighted shares on a weekly basis. However, unless you are in contention or run the threat of contention it's not really necessary as the VM kernel is a ninja. Let it be.
Andrew Mitchell's script - http://www.yellow-bricks.com/wp-content/uploads/ResPoolShares.ps1
Running PowerCLI as a Secure Scheduled Task - http://www.knightusn.com/home/runningpowercliasasecurescheduledtask
-vFantastic