How many tubes of RTV should I use...

Why the hell would you need RTV to seal a water pump on a 3.0?
There is an O-ring on the the back of the water pump that goes into the water pipe.
Other than that, I can't think of a reason to use RTV

I watched a crew install a new radiator in an autozone parking lot and then fill it all up with purple power and drive away. We tried to help, they were having nothing to do with us.

Someone probably saw the label said "for water pumps" and so they dumped it into the filler neck.. LOL.