I've attached a picture of how I set the NoMol. This one happens to be an old model that isn't plated, but the only difference I've noticed is that it takes a couple of more times setting the plated model before the "spring" is loosened up and not popping the trigger. Two things I do that makes a big difference are to preset the traps at the office until the trigger stays in place and the trap stops self firing and to make a mud ball and place it in front of the trigger when making the set.
On a normal job, I make the set by cuting a 8 - 12" opening in the mole tunnel (I only set surface runs with the NoMol) and rolling it back away from the tunnel. Next I ream both ends of the still closed tunnel to make them wide enough to insert the trap ends. Then I insert the traps (one on each end) until the trigger is about 1/2" or so away from the tunnel. Next, I make a 3/4-1" "mud ball" and drop it right in front of the trigger. This is the hardest part as you don't want the too much distance between it and the trigger, but you also don't want it so tight that you're firing off the trap while making the set. Lastly, I stake each trap end with a survey flag and close up the tunnel.