Just had a sink installed by a plumber. There was a very small leak coming from very top of drain assembly. The plumber claims that the overflow holes in the drain assmebly are too tall for this particular sink. And the fact the holes come down lower than the ceramic, that the water is leaking out the overflow hole. Though they are covered by the thick rubber gasket that the bottom nut on the ssembly pushes up into bottom of sink. Is this a common problem? Are there known workarounds? Do they make drain assemblies with over flow holes that aren't as tall? How do you know which are which as most specs don;t seem to specify this dimension. My plumber said the only likely solution was to use a drain assembly with no overflow. I don't like this option as my sinks overflow hole would then not lead into the drain.