The screws on the very back of your carbs are the idle mixture screws. These are what set your idle and use only these. Start buy turning them all the way in gently that leans the mixture all teh way out. Then turn them out .5 turns to start. You are looking for the best smoothest lean idle on these. If you have to turn them out more than 1.5 your idle jets are to small. If you have to keep them less than .5 they are to big.
Now the screw on the throttle stops are for throttle blade syncro. Dont let anyone tell you this is how you set your idle speed as they are dead wrong. Turn them all in till they just barely touch the throttle stop. Take a piece of hose and listen to each carb and make sure they are all open the same amount. unisyn is junk get a syncro meter or a hose. Hose is better than unisyn.
There is a big fat flat head screw right in front of the mixture screws its pretty big. Take that out at with the engine off. These are your progression ports. There should be 3 holes staggered in there. You want the throttle blade no farther out than the hole closest to the intake mani. Your idle will change when you adjust the syncro because you let in a little air. Re adjust mixture screws to suit. When you think you have it go to the other side and pull a plug wire. The mixture is correct when the rpm drop is the same for every cyl or close.
Test drive time. Also when you are doing the initial setup the throttle arms must be disconnected from the carbs so pop your arms off before you start. DONT LET ANYONE TELL YOU TO ADJUST THE THROTTLE STOPS TO SET IDLE. Thats not how it works and you are cheating the system and will get a lean stumble off the line because you are drawing fuel out of the well for idle and its NOT RIGHT.
If you have a issue zach call me.