Follow the rtv instructions, most of us don't read directions!
Let it all setup overnight (24 hours even better) before you add coolant.
Clean out the bolt holes in the intake, run the bolts in (by hand) till they bottom out. Make sure the remaining distance from the manifold to the underside of the bolt head is smaller than the thickness of the t stat housing.
torque the bolts to spec, not " that feels about right"
I have always had t stat housing leaks on all my cars (regardless of brand or age) till I started following my own advise.
