robin is correct (for once), i have had that i-frame apart a few times, the screw in the trigger itself works in a similar way to screw in a blade trigger, it controls how far the trigger moves post-activation.
the one in the top of the trigger, this is actually inside the frame under the board controls the tension of the spring, so you gat a choice, a hard, snappy return OR a soft, somewhat limp return... if you're feelin adventuous, you could achieve some thin in the middle.
finally the 'other' screw, this controls where the trigger starts in rellation to the point of activation, you can set it so that the trigger virtually sits on the point of activation, so that a mere breeze could make you shoot (i suggest a wee bit more ater travel if you chose this option) or you can have a little travel before the trigger activates the switch (you can get away with less after travel here)
and all that from a guy who doesn't even own one! .....does that make e a techie then?
Hp
