Changing rear differential fluid

I have 80k miles on my 2000 2dr Automatic 4x4 and want to change the rear diff fluid myself. I found some good how-to's on here but have some questions.
What is the correct gear oil to use and how much?
What is the best RTV sealant to use?
I have read that you cannot use RTV sealant if you use synthetic because it will leak. Is this true?
Does anyone have any tips or things I should look out for when doing this?

Thanks

The answer that was provided here wasn't good enough?

Please do not post the same question repeatedly.