What hole size for Williams/Bally Push Buttons?

I'm planning to use later model Williams/Bally push buttons on my VP build, but I can't find a datasheet to confirm information, or even just info on the hole size required for these. With the exception of the 2" Launch Ball button, all of the other buttons are all standard 1" buttons. The part numbers all start with #20-9663, even the larger button, so I suspect they all take the same hole size, but I'm not sure what that is. Does anyone know the hole size, or know where I can get this information?

Thanks!