Troy, try getting a hold of the spinner and the tip of the vertical tail fin. It isn't precise, but it will give you a pretty good idea. If its heavy to one side or the other, then you need to add weight to the opposite side.

Another way to laterally balance would be to get some string and hang from the ceiling. With a loop on one end, loop it around the front of the spinner and a T-Pin in the vertical. This will give you a much more accurate idea.

Hope this helps