[1QuickS]

Air flow through carbs at idle is function of throttle plates closing consistently each time and the amount of air you let "bleed" into the bores to balance for minor imperfections in component sealing, valve clearances, engine characteristics, etc.

Therefore: air flow through individual barrels should be unaffected by side-to-side balancing assuming there isn't an issue with drop links and cross bar that prevent throttle stop screws from seating as they did when idle air and idle speed was set.

It will take a couple of iterations to get idle air, idle mixture and idle speed set since making "Lean Best" mixture adjustments will affect engine speed which necessitates readjusting air screws and idle speed stop screws. All that adjustment affects air flow which affects mixture...Two iterations will usually get you close enough.

Another issue is wearing of throttle plates and throttle shaft/bearing interfaces; the more wear-related clearances you have - the more opportunity you have for air flow to be erratic. It is this issue that got me involved with my carbs and eventually with my carb service business.