Vinnie's right, you're probably close enough. Here's what I do... Set something under the spinner (like a paint can), block it up so it is just bearly touching. Then lift the tail with one finger. Do this several times. If it falls to one side every time, add weight to the other wingtip and try again. Keep doing this until it falls to either side each time you lift it. That is close enough, and for the type of flying that most people do, close enough, is well... close enough.
