Spark Plug Advice Needed

The transfer slot is down inside the primary throttle bore, on the front side, and is the primary source of fuel delivery from idle to roughly 30% throttle opening, (I'm guessing) when the Mainjet comes on line.
At idle, transfer-slot fuel is augmented by fuel coming from the Mixture screw ports.
Just how important is this? I'm asking because I looked at my edelbrock carburetor tuning booklet and it's not even mentioned