The control panel only had 3 buttons per joystick so I added another 3 for each player. I have another 2 buttons to place each side of the control box like on a pinball machine for those particular games. I use an I-PAC Interface board so I don't have to place any more buttons on the cabinet, thus it looks more original.
Here is the I-PAC in my cabinet, a better pic from his site is below.
