Look at the size of the horizontal tail... it is much bigger in relation to the size of the wing then most airplanes... the CG position depends on the size and moment of the horizontal tail, it's not always at the main spar or 25% chord.... I may open up a bucket of worms here, but with that big of a tail I bet the CG should be about 30-35% wing chord and the tail will be lifting up in level flight, rather then down.

Ty