Leaking thermostat housing, best gasket???

I've heard that no gasket and the red high temp RTV silicon works well, but there are several opinions on that matter. Do you by any chance have the chrome thermostat housing? I know those are prone to leaks.

Check your manifold to ensure that the mating surface is flat. If need be, scratch up the gasket mating surfaces a little bit, cover the gasket in the red RTV, and torque it down. That should resolve the leaking issue, if the housing itself is indeed flat.