All you need to use is Permatex clear RTV for the rear main seal. I've done a few and have never had one leak. Including the engine in my car now that i did about 6 years ago.
Just make sure you get everything clean and oil free and squeeze the RTV into the side cavities until you see it come out between the main cap and block. I use a pipe cleaner dampened with water and stick it into the RTV to eliminate any air pockets and to help the RTV cure.