Particle system Fire & Water few quesiton about my project

Hello all,
I have a few quesitons.
I want to make fire that can be extinguish by water.
When water particle collides with fire it will be realistic put of the fire.
Quesitons [i know how to make it already did but are there any other better ideas]
So i made a fire particle system that has box collider without mesh just box collider and it has tag 'Fire' and on water particle system i enabled collides on one of the particles that is water so 'OnParticleCollision' i with fire it kills/destroys the fire.
The problem is that the fire is small and i want for example set some area on Fire, so my idea is to make a middle sized particle and then copy and paste it all around where i want the place to be on fire.
Another question is this good idea or there is a way of making a big particle system with collision detection and whenever the water hits the fire for example in front then it extinguish/destroy just the particle in front ? like idk make size smaller or something [when in real life you dont have boxes you have fire and whenever water hits you extinguish fire where the water hits dont just hit a bit of fire and it goes of next even though you didnt put water next to it but its one particle ] idk if you get this last line but what i mean is if its possible to make 1 big fire particle rounded but when water hits it on left it doesnt just kill all this particle it will just destroy the particles that the water collided with. [ I add a picture for better understanding]

Thanks for helping !

 

Anyone :?