One car/TB is controlled by the idle set screw on it's stop. The other three are matched to the first via the linkage. How you make adjustments and in what order all depends on how your linkage is set up.
Years ago I worked on my linkage for a long time trying to get it to synch. Finally, I gave up. I pulled it all off and threw it away. Then I built my own linkage using a central pulley, and it synched up easily.
I started out with this. One rod crossed over from one side to the other. Never could get this to work right.
Then I changed it to this, with a central bell crank. Worked almost immediately, and stayed in tune.
