Need best method for no leaks at rearmain and oil pan

Make sure your pan bolt holes haven't concaved from overtightening. This will cause it to leak too. If they are, smack em with a hammer somewhat gently til they flatten out. I just use a lil rtv to attach the cork gasket to the rubber end seals and torque it down. This is the way I was taught and never saw a leak. I also use a very very light coating on the rear main mating surface to the block of RTV.