This might not apply since I run a pickup, but it might give other readers some ideas:
You are supposed to avoid blinding the driver with the nozzles. Other than that, I used my best judgement. I have two separate systems, one 10lb system for the driver (Cold Fire), one 10lb for the engine (Halon).
I run 3 nozzles inside (large cab):
A flat 180 deg nozzle that sprays from the upper center passenger side aimed at the top plane of the cab, much like a sprinkler system in a building.
A flat 180 deg nozzle that sprays from the lower center passenger side aimed at the bottom plane, so if the truck is upside down, it has the same effect.
A flat 180 deg nozzle that sprays from the middle center of the cab towards the driver mounted at a 45 deg angle so it hits me from helmet to shoes.
The third nozzle is the one that I expect to save my life. Most all of it's Cold Fire suppressant will actually hit my body to increase the firesuit's survival time.
The other two should be able to put out the fire.
For the engine:
A 3-hole 180 deg nozzle aimed at the exhaust manifold on either side
A single port nozzle injected into the engine intake manifold directly. This is diesel specific, to stop "runaways". If a diesel gets oil into the intake (blown turbo), you cannot shut engine off by killing the fuel or electrics. The Halon will do it.
If you do get into a fire situation, nobody can help you for a few minutes, and you might not be conscious. It's the nature of LSR racing. Don't skimp on fire protection.