RE: Yet Another CG Post ...
All of thease answers have been correct. As long as you're in the recommended range, you'll probably be alright since the recommended C of G range is usually a little on the conservative (aka nose-heavy) side. I was a bit surprised when I said never go outside the recommended range that some of the 3D guys didn't harpoon me. They routinely set the C of G back farther than is recommended by the designer. It helps to keep the tail under them in hovers and is the reason the planes snap around as quick as they do. I should have specified that you shouldn't go outside the range on a trainer. Trainers are rarely used for 3D flying. My 2cents on setting the C of G on a high performance airplane: Start someplace inside the recommended range, fly the plane and see how it flies, move the C of G back 1/8", repeat. Keep moving the C of G back until the plane starts to get a little too squirrely for your taste, then move the C of G forward 1/8". The plane should have the maximum elevator response that you can comfortably control. Mark this spot for future reference. I've never seen a CG Machine at the field. Fingers serve the purpose.