New setup help

16'x18'x7.5' room with( 2) open doors leading into s basement/garage area (1) window
I've painted walls with flat white paint buying a ventilation kit tomorrow with a 998cfm or higher airflow Also picking up panda film for the open doorways. Setup the 5x15 scrog netting. Im trying to figure out how to space the 4 Phantom CMh 315 lights(i may not need all 4 ) going to by a bag of co2 .. okay what have i missed and any ideas on spacing the reflectors. Currently have two plants going. Only 1 is in the room now.. soil FFOF will be used for the clones I'll be purchasing fir the room. How many should i grow in a room that size and under those CMh 315 lights? Thanks all suggestions are welcomed and very much appreciated

A 315cmh covers 3x3, some say slightly less but if your using multiple lights then 3x3 per light is no problem.
So your looking at a grow area of 6x6 and you have a massive amount of spare space left.
So i would go for that, one per 3x3 maybe stretch it out slightly, but you will get some good coverage and great overlap like that.

As far as plant count goes, its preference, but if your looking to scrog properly i wouldnt go more than 4 plants per light.

You might want to hang panda film around your grow, where your not against walls. Some nice panda curtains.

Im assuming when i type all this that you do mean 315cmh and not 630s or bigger!

Edit, if you already set up a scrog net you might want to run all 4 lights in a row, but i think they are better suited in a square to get better overlap.

That's the explanation and answer ive been searching for... Thank you.. Im going to be putting things together slowly.. i really appreciate your help and you explained well enough that even i understood. Life has placed yet another challenging shit storm to navigate through.. i'm going to eventually Enjoy a properly grown bud from my own garden... thnx again my friend. Enjoy your day..

Panda film is going up today and so are two more lights. Thanks again for your help. I'm going to hang the reflectors in a square. Leaving 3' distance to take advantage of the 3x3 footprint.. enjoy your day my friend