I spent some time this week tuning my car. After setting the valves. I'm able to check/set the valves without jacking the car. I move to TDC on 1 then routine the engine anti clockwise 180 degree (backwards) to check 2, 3 and 4.
Next I check the timing. I've always had issues with my timing light and the advance function on it. I don't believe that it's calculates the advance correctly. I've found that the timing light isn't stable with a larger advance on it. Therefore I always use the light with zero advance and I've marked 30/35/40 degrees advance on my pulley wheel with tipex. The straight line distances are
30 = 37.6
35 = 43.6
40 = 43.6
Using this method at max advance I get a very stable flash on the 35 adv mark. Which I guess means that I've about 5 degree static adv.
Next I've found that getting the carbs balanced is the key to smooth idle. I use one of these
I remove the filters. Getting the left to right is pretty straight forward by adjusting the idle speed screws. However, I only recently found about the air bypass screws which allow you to balance each carb barrel in the left and right sets. I've found that this is another important step to getting a smooth idle.
Next I get a, often none, willing help to set in the car and rev the engine to 2k and 3k so I can check that the carbs are still balanced. If not I adjust the linkage. If I have to adjust the linkage than I have to rebalance using the idle speed screws.
Once I'm happy with the balance I put the filters back on and I try to set the balance on each carb. I use the idle mix screw to find the max rpm. I often use an external rpm meter to help me. I back the screw in until the engine slows then I back out until the engine slows then move back in until I get the max rpm. Often all 4 carb have to be set nice before the sweet spot is found. I've found this to produce pretty good results. I've read that some people then like to set the mix a little rich compared to the sweet spot.
If the car doesn't run smoothly after this then you may have a bad mix of idle v main (for weber often 55/115) jets.