The MaGUI mod has documentation inside the download on how to use it specifically. It uses specific marks on the wheel to read off the range and speed.
For the OLC mod, it works similarly, but OLC explained it in a video tutorial. You'll have to be patient for a while still. I'm currently uploading it to my Gamefront account. (see link below this)
http://www.gamefront.com/files/21408...+Tutorials.rar