Its just a thought. It appeared to me that the back end of the fuselage was hanging down a bit. Like I said, judging by the way it flew, the cg is fine for the wing position as it is. But, the horizontal stabilizer provides down force to counter the nose down pitching moment (torque) caused by the shape of the airfoil. It seems to me that, by moving the wing slightly back the moment arm of the horz stab is reduced. I can't tell you a specific distance to move it, but it won't be by much. This will allow the fuselage to be more horizontal in flight, reducing drag and making the whole thing a bit more efficient. If you move the wing back a bit, you can reduce nose weight, if you had to add any extra to get the cg balanced. However, if you are happy with the way it flies (and it looks like it flies quite well!) then don't change anything!