Streamlight TLR8 is the only laser/light I know of that will fit. Iím sure there are others. Itís tough to get both laser and light is that short a space.
If your willing to let the light extend slightly then you can increase the brightness and battery. Like the olight Balder is more than double the brightness of the TLR8 but itíll extend past the end of the slide a bit.
You donít need to add another rail, the lights will mount better directly on the Glock rail.
Sent from my iPhone using Tapatalk