If you have neopreme(sp?) gaskets, I think they are supposed to be put on dry(no rtv). I likey the cork ones, and just silly cone the valve cover side so I can reuse them.

Which valve covers did you get?  I have mine custom made and engraved.  They are pricey but do not leak.

I recently looked at some cheaper imported ones and even at less than have the cost of mine, I would not put them on an engine that I build for someone.  The flange was thin, crude and rough, and nowhere near straight, I placed two of them flange to flange.