You are not really looking for good air to fuel at idle, you should look for strongest vacuum signal. Sometimes people try to get the lowest idle RPM wise they can, too. Quadrajets run down the road on your jet size, rod size, and power piston spring size, ie, the primary circuit so checking A/F at cruise down the highway will help there.

At idle, you want smoothness and "good running." At cruise, you want economy, so tune a/f there. At secondaries, you want the hammers of hell, so as big of jets as that thing will handle without bogging is usually good.

 

 

14.7:1 is perfect stoichiometric AFR. 14.2 is slightly rich but very slightly. Id say you are good at that AFR. Run it for a few 100 and read the exhaust tips and plugs. That will tell you which way you need to go on the A/F adjustment.(and rods & jets for more extreme tuning which you likely don't need as it was just blueprinted?).
Adjust the timing while it's running to achieve the highest vac reading. Then go at the A/F screws and back in forth to obtain the highest manifold vac reading