Trackball Dimensions for Control Panel?

[Jdurg]

I'm trying to work on the layout of my control panel but one thing I can't seem to find is the amount of room needed for a trackball.  How much space needs to be left for a trackball in a control panel?  A 5"x5" square, a 4"x4" square?  I know that underneath it requires a bit of space and I'm just trying to work on the positioning of the components of the control panel and want to be absolutely certain that everything is positioned right.  I hope to start making my first cuts this coming week!   

[unclet]

For Happ trackballs, go to www.happcontrols.com, click on Trackballs from left side menu, select specific trackball, then select the "Mounting and Exploded Views" circle which is midway down on the page.  You will then see all the parts which make up the trackball as well as the dimensions required for mounting.


for example:
http://www.happcontrols.com/trackballs/560100e.htm