The air bleeds, high speed and idle affect the mixing of air and fuel in the carb. I look at the percentage of difference in hole sizes when changing the bleeds, a .027 bleed compared to a .029 bleed is substantial difference in the percentage of the hole sizes. Bigger bleed hole equals more air with less fuel, less hole size equals less air amd more fuel into that circuit The idle circuit bleeds affects the air fuel ratio from idle to W.O.T no mattr wah the RPM I remember a statement in National Dragster that the Pro Stock teams didn't change jets in thier carbs. once they had them dialed in from Denver in the summer to Pomona in the winter, they would and did change the bleeds for each track and weather conditions on a regular basis
Tune off the spark plug and time slip for that day, unless you buy and use a wide ban Once you get the car as good as you can from jetting then try tuning the bleeds IHTHs