It could be simple. It "seems" to be balanced right, but try putting the plane in a dive and then suddenly cut the power to idle. If it begins to pull up and level off on it's own, then it is too nose heavy. Move the CG back some, retrim for level flight, and try the dive test again. It should then continue in the dive or just pull up ever so slightly.

Now that it has been retrimmed for really proper CG, the balooning on landings should disappear!

Ernie