Dave,
Could it be that the model is so nose heavy that the trim is needed to maintain level flight, I have seen it. It is hard to say the incidence is off by looking at a picture, for me at least. That's not to say it isn't off, just that it is hard to tell from looking. As far as CG goes it is stated to be balanced on the main spar which for that plane is a safe starting point, very safe. So in my opinion it is stll just a CG problem if you want to call it that. It is however where I would make the first adjustment before getting the incidence meter out.
Not trying to step on any toes here, just looking for the easiest fix first.
Tim