Things are a bit confusing with the Glock because the main trigger resistance comes from the striker spring. Opposing the force of the striker spring is the trigger return spring which operates on the connector bar. The standard trigger return spring is a coil spring which results in the standard 5.5 lb trigger pull.
There are two "NY" leaf-type trigger return springs that also increase trigger pull; the olive colored NY1 which runs about 8 lb, and the "NY+" or "NY2" which apparently runs about 12 lb. I have the NY1 spring in two of my Glocks.
There is also a 3.5 lb connector, which operates in conjunction with the standard 5.5 lb trigger return spring, to give a roughly 3.5 lb trigger pull. The light trigger is nice, its nowhere near what a good SA trigger can be but its good enough. But strangely some people shoot better with the NY1 trigger.
For real world self defense, the NY1 spring is fine. When I took LFI-1, I did the qual shoot with my model 26 which has a NY1 spring. The only guys with higher scores had tricked out .45s. Had I practiced a bit more before attending, and used a model 22 instead, I would have beaten at least one of the .45 guys. But I wanted to qual with my CCL gun. What's the point of qualifying with the easiest gun to shoot? I've proven I can shoot minute-of-bad-guy with a pocket pistol & a NY spring, given that the overwhelming majority of gunfights happen inside of 15 ft I have oriented my training and gear accordingly. I'm not planning on headshots at 25 yards, I have other tools for that.
If you're going to do gun games, you'll want to use the standard spring and a 3.5 lb connector.
There is an obscure option; combine a 3.5 connector and a NY1 spring. It gives a roughly 5 lb pull but is almost DA revolver-like, very constant level of force throughout the pull stroke which makes striker release more of a surprise. I tried it for awhile, kinda liked it but worried about reliability. So I took it out. Now I have two NY1 springs and one 3.5 connector in my Glocks.
Get a manual which describes detail stripping the Glock, and mailorder the pin punch, one of each kind of spring, along with a 3.5 connector, and have fun with it. The overwhelming advantage of the Glock is that new OEM parts are dirt cheap, and anyone can replace them in a matter of minutes. Hell, if you practice you could swap out the return spring in about 20 seconds if you're coordinated.