Man ....That's a hoss!!!! I ended up using three Fromeco 7.4v 2400MAH. The only thing is it looks like my CG is going to be a tad forward then I thought it would be. I ended building a tray with the extra spare wood.I mounted it aft the pull-pull rudder servo to hold two of the batteries. The other battery I will mount just forward of the rudder servo.
In all honesty, I probably could install the rudder servo in the tail and get a lot closer to the wanted cg range.
Here's a couple picture of the tray I built tonight.