CG Question on a new Do.

Okay, let me see if I can explain this correctly. I just finished my DO. I am using a Great Plane GC machine. When I tried to balance it is was really tail heavy. I moved the battery over the fuel tank and it took a little weight up front to bring it close.

Now the strange part: I could make it balance nicely on the bubble if I put it there it would stay. However if I tip it more than just a touch forward or aft it tilts all the way in that direction, and will not balance itself out. On past planes I have balanced when it was done right you could push on the tail or the nose and it would go back to level. Also had a hard time figuring out exactly how to put the plane of the balancer without pokeing a hole in the wing. I decided to place a peice of cardbord under each wing to distrubite the load a little, I would like to know how others have balanced this plane?