If I understand you correctly.... you mean how "deep" the control panel box needed to store the joysticks, buttons... etc. right ??..
Most joysticks, buttons, etc... usually take about 2.5 - 3 inch clearance and you should be good....
but if you're going to install the DOT spinner... you'll need more space.... 4 inch clearance.... (I ended up have to get the Torando Spinner because I can't fit the DOT spinner on my panel....)
good luck....