I'm on my third rear end since I started racing these cars, they bend so easily and a bent rear will kill speed quick. I know my torque wrench would be a pain to get in their if the rear was in the car. I have always gone palm tight with a 1/4 ratchet. I have never had an issue with it coming loose, but I have had studs strip and turn from over tightening.
As Steve said, very thin layer of silicone on the gasket will keep it from leaking.