The dashpot plunger is to be in contact with the screw, rather it should press a little further. When the engine starts the plunger pulls inward. When you increase the rpm, the plunger comes out quickly. When throttle is released, it is held by this plunger a little and then the plunger slowly goes inward, thus decreasing the rpm slowly but only near the idle rpm.
I think you can adjust it for your ease now.
No. 6 is to be connected such that it bypass a little amount of air to lean out the mixture when the engine is hot enough. Leaving it open will let the dirty air go into the carb top and also disturb the idle.
No 9 looks a mixture set screw to me. And 10 is a port that is plugged.