jag running rough

i believe it is common for jags to leak from the hoses coming in from the railing. i had the same problem; i saw some gasoline pooling near the intake but also saw a wet hose. so i tightened it, and then read up on it. found out... it happens. so always keep a screwdriver in your car. about the rough idle. it is also something that i'm always batlling with. so far, i can make her idle on Park/Neutral at 700-800rpms. achieving this with the "idle SPEED screw". but when i pull it into Drive, she has fits about it.
so then i go to the idle MIXTURE screw (that, for some reason, no one dares mention)
and when i screw it in all the way. the car keeps running, which boggles me (car shakes but stays on). i notice that if i only unscrew it 1 or 1.1/2 turns out. it idles better. but i don't know this to be a good thing.