[xlr8or]

Idle mixture screws are at the base on the front of the carb but they really only adjust the initial butterfly opening. You'll need to start with jets that are close to correct and go from there. The edelbrock carb uses metering rods with two sizes that sit in the jet to adjust for cruise and WOT. Transition from part to full throttle is controlled by the springs on the metering rods. You can also adjust the accellerator pump if you are stumbling in transition from fuel starvation.
Get it close and then go to the dyno where a/f ratio can be monitored and adjusted as needed. You can buy an adjustment kit with an assortment of jets and metering rods and springs. Take that with you to the dyno. If they are familiar with the Edelbrock or Carter carbs they should be able to dial it in pretty well.