the inlet needle. Or test as described in the workshop manual. Pinch the fuel line to see if the needle holds pressure. Snug and a little bit more. It has to be tight or it will leak.
2.Sounds like your fuel level is high, so try a thicker gasket on the fuel inlet which controls the fuel level. First measure and record who put what in there.
BMW describes two thickness. Mercedes had 7. There was a reason.
3. Floats are brass. Not likely to leak. But if they do, you'll know it. Gas everywhere. Shake the float- there'll be sloshing going on. No, you can't solder it. See 4 below.
4.No, the floats are a specific weight. No substitution unless you really know what you're doing. The tolerances around the float are such that it's easy to screw it up with even the slightest gasket mismatch.
5. Hot- when the engine shuts down, heat will cause the fuel to increase volume. Sometimes this causes hot start problems and maybe the fuel you see around the screw. Got spring washers?
6. Adjustments, there a range of idle/ open throttle/ and relation to rich. Simple way is a vacuum gauge to highest and best reading. But both carbs should be about the same in adjustment. Count the turns on the idle screws and think watch adjustments. Small and deliberate.
Show some pictures of the plugs, etc.
See 1 and 2 above.
i would not dare to contradict my master,
but my floats are made of plastic, just in case,... that being said makes no difference in the conclussion, if float is NG (thanks again Steve), or stuck in the gasket (was my case), gas will be filling everything, everywhere, including manifolds, a terrible mess
i agree we should be told a bit more about adjustments and fittings to know from were we are departing,
fuel traces in the carbs do not always mean fuel leaks, and there are fuel traces and fuel traces, it might be subjective, pics will help to set the treshold
p.s. a simple fix might be to do the top bolts a bit, as gaskets get compressed with heat, use and fuel mist i find that some thousands of km later bolts can be thigthen a bit more so any gap would be closed, maybe this works for you...?
regards