Time pilot,

You are correct about the long mounts for adjusting for a tail heavy condition. In fact, this is often over-looked as the best way to adjust for proper CG without adding weight. Another factor to consider is the type of plane this will be mounted to. Some planes accept longer mounts easier than others depending on type of nose configuration. If it's an open type, then it's usually easy to do, however, if it's a closed type that terminates with a spinner ring, you will have to measure how much room you have to play with.