I’m not a well known carb guru, and don’t have nearly the experience people like Mark W have.
That being said, I’ve never bothered messing with the idle circuit to cure a “bog” situation that occurs when going from idle/just off idle to WOT in a tenth of a second.
Maybe I’m missing the boat, or maybe I’m just lucky.
Think of the countless QFT carbs, among others, who are enjoying bog-free operation out of their foot brake cars that still have the IFR in the upper location.
All the messing around with the slots and IFR location seems like it comes into play more when trying to sort out “drivability” problems.
My “good” carb is a CFS built annular booster old school Holley 850 I had done in 1990.
It’s a great foot brake bracket race carb, but it’s pretty rich at low speed part throttle operation, so..... as it sits it wouldn’t be a great street carb.
But, I have other carbs that work fine on the street.