Sanus, the sister company of Chief and arguably the originator of mount-finder tools,  has a solution that may be the most robust of those tested.

While their main mount finder tool is on par with Chief’s, they also have an additional Height Finder that lets you input parameters like Brand/Model, Mount, and desired height. It then calculates where on your wall you should drill your holes and even provides a helpful visualization diagram.

The combination of brand support and the Height Finder tool makes Sanus’s tool the best I’ve seen.

Kind of makes you want to buy a Sanus mount.

http://www.sanus.com