Might I suggest that not moving the ogre is possibly preferable. During a phase change the ogre may use his ranged attack on the tank for about 1200-1300 damage. In and of itself that's peachy but if he chooses to do two back-to-back, and he has and does, your healers may not be able available in that 1-3 second window during the shuffle to prevent the tank from dying.

Credit goes to Matriarch and their Italian friends for this video and I reference it only insofar as it is a good illustration of positioning in a "don't move the ogre" scenario:

http://www.youtube.com/watch?v=L26WKKKMy8I

MP conservation is definitely key during this fight and it is among the most important aspects of it. But I submit to you and the community that reducing the potential for error as the margin for error in this fight is so slim is key. The scenario in which both the tank and his Ogre friend (as one group) and the melee (as another group) and the archers/casters (as a third group) are all moving throughout the fight during phase changes is orders of magnitude higher in its error potential than a situation where the most dangerous element, Mr. Tank and George the Ogre, are predictable and stationary, while the rest of the group moves around that focal point.

As a benefit this allows the healers to pivot around that group never being out of healing range and the predictability also allows for very safe and regular use of Spiritbind. You'll also note that the strategy depicted in the video is not reliant on stacking archers, which is a boon to the rest of the sad-face melee who are last picked for the softball team.