Idle Transfer Slot on secondaries?

Bewy, I hear and have seen how A significant Advance like 43° at idle can smooth out the idle. But if the mixture is off due to lack of airflow because of the throttle plate exposing to much of the T-Slot then it seems to me (not claiming to be an expert here) the added advance to compensate is not the right approach. It masks the fundamental problem of a bad mix.

Seems like tuning is an iterative process going back and forth from carb adjustments to timing tweaks.

I did buy the Progression Distributor so I will easily be able to modify the curve at will and on the fly. But I need to have a tuned carb that isn’t way off like I feel it is right now.

Does this make sense? I am trying to learn here and this thread has been excellent for me.