I'm actually t&e'ing the RDIH ambi thumb safety for Glocks. It works on a mechanical impingement process, and Vega Holsters has provided a Level 2/3 duty holster for a Glock with the safety system installed, and BH Spring Solutions has an adaption kit for similar Safariland holsters.
Mechanically, the system works well, but I have some qualms with it in that to deactivate it you (or at least me specifically) have to move out of my firing grip. There's also a modified field stripping process involving using a simple provided tool.
If used in a duty gun in a level 2 or level 3 holster, I'd probably use it with the safety off, and just use the manual safety administratively (i.e., when degunning after a shift or for nightstasnd defense at home).
I'm discussing how the ergonomics can be relatively easily improved with the partners at BH SS; basically I think that the "pedal" portion of the safety's pad needs to be re-angled, and the lever possibly extended slightly (but the re-angling of the actuating pad might be sufficient).
https://bhspringsolutions.com/index....-optimization/
https://pistol-forum.com/showthread....ring+Solutions
Best, Jon