RE: changing your CG?
The CG that is in the instructions or plans is for the most part, a starting point. If you balance it here, the plane should fly fairly stable enough to guarrentee a good test flight. The CG should only be adjusted after a few flights unless of course the plane feels unstable and is overly sensitive at landing speeds, and maybe doesn't drop the nose when reducing power. In this case you would consider moving the CG forward. If you move it back the plane begins to "come alive". In addition to becoming more sensitive to control inputs, you will find that it will most times land slower and use less elevator. So expect as you shift the CG aft, you will need less elevator throw. Moving the CG either direction can fine tune your airplane to your flying style. It can make it more stable on final (fwd) or perhaps hover or roll better(aft). But if you move the CG move it a small amount. Maybe 1/8-1/4" at a time then evaluate it over a couple of flights. Most importantly remember that nose heavy planes can be hard to fly slowly, but tail heavy planes are hard to rebuild.
Skip D