You have to take great care when fitting the tail section and joining the main wing of this plane together for it to come out right. I had to do a little sanding to get it right but the plane came out as straight as an arrow. My incidence is a perfect 0 degrees on the horizonal stabilizer and main wing and the main wing's leading edge is perfectly straight. Take your time and do your homework on this one. The results are worth it. On the CG issue I am presently flying this plane at 4" and the plane handles great. It does not matter if the cg was checked upside down or right side up on a midwing.