How to maximize Macbook pro retina's battery life when working with AC power?
It's best to follow the guidance of Apple: http://www.apple.com/batteries/notebooks.html


  Standard Maintenance
  
  For proper maintenance of a lithium-based battery, it’s important to
  keep the electrons in it moving occasionally. Apple does not recommend
  leaving your portable plugged in all the time. An ideal use would be a
  commuter who uses her notebook on the train, then plugs it in at the
  office to charge. This keeps the battery juices flowing. If on the
  other hand, you use a desktop computer at work, and save a notebook
  for infrequent travel, Apple recommends charging and discharging its
  battery at least once per month. Need a reminder? Add an event to your
  desktop’s iCal. When your battery no longer holds sufficient charge to
  meet your needs, you may choose to replace it. If your notebook came
  with a built-in battery, you should have the battery replaced only by
  an Apple Authorized Service Provider.
  
  Long-Term Storage
  
  If you don’t plan on using your notebook for more than six months,
  Apple recommends that you store the battery with a 50% charge. If you
  store a battery when it’s fully discharged, it could fall into a deep
  discharge state, which renders it incapable of holding any charge.
  Conversely, if you store it fully charged for an extended period of
  time, the battery may experience some loss of battery capacity,
  meaning it will have a shorter life. Be sure to store your notebook
  and battery at the proper temperature. (See “Notebook Temperate
  Zone.”)


Basically what it says is use your Macbook in whichever way is comfortable to you. If you prefer to use it plugged into AC at all times, just make sure to disconnect it at least once per month and let it discharge to make sure the electrons moving around inside it.

Cycles are based on a cumulative basis. If you choose to let it go down to 50% twice, that's one cycle. If you chose to let it go down to 75% four times, that's still one cycle. The cycles will go with normal usage and you'll be much happier if you don't worry about it too much. The hardware is designed to last much of the life of the unit since the switch from Li-on batteries.

Contrary to your post, Apple DOES NOT recommend running laptops with removable batteries on AC without the battery: http://support.apple.com/kb/HT2332

Please check out this link from a less official, but still helpful source: http://forums.macrumors.com/showpost.php?p=9875442&amp;postcount=23