I looked a video, and another website showing "the Glock Adjustable Trigger", and noticed the effect the adjusting hex head screws had on the trigger housing...namely inside the slot that controls the trigger travel.
It essentially modified the opening that the cruciform on the trigger bar slides into, and limited it's range of travel...both creep(before) and after travel (after firing).
So, not wanting to spend the $100+ for the adjustable drop in trigger. I limited the travel range simply by using a tiny bit of JB Weld in the slot of my Glock...and it worked perfectly, after some dremel tool slight "adjustment" to the JB Weld.
Please forgive my crude drawing below.
The black is the stock slot, show green as areas where JB Weld was added to limit the trigger travel.
click on title----->http://s195.photobucket.com/albums/z296/daddySEAL/