Stromberg float chamber leak

[Robmsharp]

I have stripped down and rebuilt my Carbs using new gaskets throughout, but after putting the carb assembly back on and allowing the pump to fill the system I've noticed that I have a slow drip of petrol coming down two of the float chamber screws on the lowest side of each carb.
I've taken the carbs back off and inspected the gasket that seals each float chamber and I can see where the little ridge running round the chamber has left a witness in the gasket which I presume is meant to act as the seal and this looks good, so I'm at a loss what to do to get a good seal. Can anyone recommend what to do, can I use a gasket sealing compound for example?

[38rover]

You may need to check and reset the float height its a fine adjustment also new float needles would be a good idea.I also fitted a pressure adjuster to keep the pressure from the pump down to 2.5 ibs

[Robmsharp]

Thanks for the advice, in the end I stripped down both carbs again and fitted another pair of new gaskets which seemed to do the trick.