im not a carb guru,but my 3 circuit runs rich even after buying the complete assortment of air bleeds.i bought a aem air to fuel ratio gage to monitor.ive heard the three circuit is main advantage is transbraked vehicles at the track.
if your gonna be driving on street ive heard 2 circuits are better.
if your gonna be racing primarily then 3 circuit.
if no racing at all and want to get easiest carb on the streets get a 4150 series,they make em up to i believe 1000 cfm.
good luck russ