I disagree. Do not stage the LEM trigger. This is a mistake a lot of people make with Glocks and other SFAs. Staging begets anticipation, anticipations lead to the misses, misses lead to the dark side...oops, wrong topic. Staging will also slow you down considerably (10ths of a second) when trying to go fast.
Pull the LEM trigger straight through. When you let the trigger out, do not hunt the reset (another horrible Glock habit). Roll the trigger smoothly out and smoothly back.
This method of shooting is very similar to a DA revolver and seems to have been lost in the time when everyone transitioned to SFAs.
Here is how to practice. Pick up a shot time (or metronome). Set a random start time and a par time of ~0.5 s to begin. Start with your finger just touching the trigger. The goal is break the shot in the par time without disturbing your sights. Start decreasing the time. Once you get down below 0.3 you will see that trying to stage the trigger is impossible if you want to keep up with the time. The goal here is ~0.2 s trigger pull without disturbing the sights. It may seem frustrating at first, and you will likely have to experiment with finger position and grip size to get it right. However, this is the only way to work a long pull trigger at speed. Modern SFAs are very forgiving triggers when it comes to bad habbits (staging, hunting the reset), but the LEM is not. I also encourage the same technique on any non-SAO pistol, you will see your accuracy at speed greatly increase.