How much does 1 jet size affect A/F?

You are sure this test works on a 650 AVS correct? I mean the Quadrajet has a idle circuit that works together with the primaries IIRC, but the 650 AVS has a totally separate system, keeping the idle circuit separate from the primaries. So could that change the way the test works...?

I'll give your suggestions a shot, but I can't understand how going leaner on the primaries will positively affect my already too lean (16 A/F) part-throttle situation...?

Ha ha, sometimes it feels like I'm getting deeper and deeeeper into the forest LOL