I took a shot at rebuilding my carborator recently and found this exploded view of the parts on the internet. The Part 51 is the 'Idle Adjusting screw' (air to Fuel mixture screw?). Mine were out 2.25 turns when I took it apart so that is where I put them back to. I don't have a vacuum guage but heard that you can, at idle, adjust them in and out until you hear the engine bog down and set half between these two points as a start. I didn't have much luck at trying this so I just put them where they were before, I ran them all the way in and backed them out 2.25 turns.
They take a 3/32 allen wrench. If the cap, part 52, is there. the rebuild kit said to put a #8 screw into it and hold the cap while turning the screw to get the cap to back out. The caps weren't there on mine when I took it apart.
The vacuum lines were shown on a diagram sticker inside the engine compartment on the driver's side wall on my W150. The diagram showed where the all went to, you could use this to check if they are going the right places. I have found this pretty difficult though, to track them around the engine.