
My aim is something like to open 20 switches in roughly 1 minute. And I mean switches, which are loose, not mounted!
I do it by hand, you basically use the retention clips on your "opening" top as levers on the switch you want to open. Do one side, hold it open with your finger whilst you pry the other side. It takes a bit of practice, but once I've got in the swing it usually takes a few seconds per switch.