Holley idling issues

Seems to me that all the old school DPs had 4 corner, and then they got cheaper in design, if I recall right?
Other way generally. Most of the classic 4150 double pumpers were 2 adjustable idle mix screws. 4777, 4779 et al
Four corner is useful for engines with poor vacuum at idle. Four corner doubles the fuel available under the throttle blades which can be a big help with idle vacuum at say 8"Hg.