Simply screw the idle mixture screws in till they stop. Don't try to tighten them. Then back them out 1 1/2 turns. At this point you don't need to change the metering rods out, just the springs. The reason you wan to change the springs is that the stock springs are too heavy for the amount of vacuum your engine is producing (based on your cam) which is causing an over-rich condition at idle and is probably also contributing to your hesitation problem. These springs come in Calibration Kits
and you'll want to use the lighter ones, probably yellow or orange. However, you can tune the carb all you want and it still won't help your streetability much because you're using the wrong intake manifold for your engine combination.
"When buying a used car, punch the buttons on the radio. If all the stations are rock and roll, there's a good chance the transmission is shot." - Larry Lujack