Maybe too late to help, but...
Back off the big idle knob adjustment so the slides bottom out, Make sure the fast idle cam on the choke mechanism is also NOT blocking full slide closure.
Since # 2 is non-adjustable, back off the individual slide adjustments on the others until # 2 is fully floored in the carb bowl. During this, make sure the big idle knob and the choke cam are not giving interference.
Now adjust #1, 3, 4 in turn so that they, too, just rest on the carb throat floor.
Now turn the big idle knob until the slides are about 1/16 open on the engine cylinder side.
Reinstall the carbs and run the engine. Adjust idle knob when warmed up and choke no longer needed.
Vacuum synch the 1,3,4 carb to match # 2. Do this after you have completed all the other standard tune up items. Tappets, cam chain, points/ timing. Plug gap/cleaning, air filter, etc.
Then do the Idle mixture screws for max RPM, while resetting the idle knob for correct idle speed.
Cheers,