Mine is at 6" and it is VERY pitch sensitive. It just plain flies tail heavy at that CG. But, I am running some expo and just a little elevator throw on low rates and it is a blast! I would like to have mine in the 5 1/2" range but don't want to add the lead to get it there. I might eventually but I want to fly it some more. I have a zdz40 on it and it weighs 16lb. Great combo.