I only use permatex RTV black on the oil pan gasket just a little on the gasket and under the rubber ends, always put it on the block side to help keep it from shiftng but just a little ,not enough to squish out just enough to hold it in place, and a small dab where the rubber and cork meet. I have been doing it this way for a long time and have not had any leaks. I have used this method for over 20 years and many engine builds after reading an article on engine sealing in a hot rod magazine.