Without going buck wild, there is a quick way to remove a great deal of pre-creep from a single stage trigger.
Set the selector to safe, re cock the action, now cheek to see how much travel you have on the trigger from rest until it maxes out against the selector (read hammer can not release since the selector has it blocked, but you still have trigger travel from at rest to against the selector). It's this travel that you can remove safely without worries. having mod any of the FCG parts.
The option are to buy a new pistol grip set screw that has the inner adjustable screw on it, or to just buy a 1/4"-28 pitch, 1/4" long allen set screw, and shorten the pistol grip screw by 3/8".
Since the set screw screw is the cheaper option, let just talk about it.
With the grip, and FCG removed for starters, you going to insert the small set screw up the threads of the receiver until you have about half of the threads above the bottom of the receiver. Apply a light coat of Blue loctite to the exposed threads of the small set screw, then screw it back down the channel until the top of it is flush with the bottom of the receiver void. Now reinstall the FCG inner workings, then with the selector set to safe, and the selector detent pin in the channel and using a small punch to push up on the detent so it centers out the selector on safe (detent tight in the selector groove for it), go back and now tighten the set screw upwards until turning the selector from safe to fire takes a slight more pressure than normal.
Note, the selector to back of trigger will slightly wear-in quickly, so go for the tighter side to begin with, instead of on the lighter side to turn the selector, and having to go back in later to readjust the set screw.
What is happening is the tip of the set screw is pushing the back of the trigger upwards, removing all that extra creep that is not needed.
As for the pistol grip screw, again, it needs to be shorten about 3/8" so when it is installed, it does not max out against the new installed set screw up the channel above it.
As for the other screw, pretty much adjusted the same way, but since there is an small inner set screw through the standard pistol grip screw, you can adjust the creep out with the pistol grip/screw in place.
http://www.brownells.com/.aspx/pid=307/Product/AR-15-M16-DROP-IN-TRIGGER-ADJUSTER
As for going for no creep at all (read bench rest type trigger),then you need to shim both the trigger and hammer to remove unneeded side ways move of both so you can perfectly match the seats to each other square, reset the sears, and even re-time the disco as well (read not for the novice, but I have a few of my bench rest/long range AR triggers set this way down to under the 2lb marks). Also to note, when doing a trigger this way, the smith will need the entire rifle since the trigger has to be set to that specific receiver.