We drank these wines together at a nice dinner last night, and it proved to be an interesting experience. My understanding is that the Corcelette is the one for earlier enjoyment while the Cote du Py requires more time, which is why we were quite surprised at just how pretty the Cote du Py started out.
The wines were decanted for an hour before being poured back in the bottle and transported to the restaurant. The Cote du Py was fresh and lively with bright high toned fruit. It was smooth and elegant and well focused, until it started clamping down about an hour later. The Corcelette had more power, in both the nose and the palate. It was meaty and earthy, showing black olive, dark juicy fruit, and good acidity - a real savory richness. At about the time the Cote du Py was clamping down, the Corcelette was becoming softer and sweeter.
Hard to find fault with drinking these wines now - they are gorgeous.