The middle and right button overrides can be used to temporarily select any of Stradview's tools when you depress the appropriate mouse button. Releasing the button returns the tool selection to its original state.
The 'Mouse selection range' slider determines how close the mouse needs to be to any object in order to select it. If you want to point less precisely, set this to a larger value, but not so large that you find yourself selecting objects you do not wish to select.
The 'Cursor rotation' slider determines by how many degrees the 3D window or reslice will rotate when the cursor keys are used.
The 'Cursor move' slider determines by how many pixels the image or ortho windows will move when the cursor keys are used.
The 'Scroll zoom' slider determines by what percentage the zoom will increase or decrease when the mouse scroll-wheel is used in any of the image or 3D windows.
All these settings are saved in your personal configuration file ('stradview.ini') so there is no need to reset them every time you launch Stradview.