W126 ignition switch screw thread size

[AUDIBLE]

1987 300SDL

I'm replacing the electrical ignition switch, which is behind the lock tumbler. The switch is held to the assembly by 3 screws that are difficult to get to. I remember a suggestion that one can substitute allen-head screws or bolts in this application to make r/r easier. Since by the time I get the switch out of my daily driver 300 SDL it won't be running, I'd like to buy some matching allen screws before I start. Anyone know the thread size? It goes through a 4.3mm bore in the switch and should be about a half-inch long.

Thanks
Bruce S