New grow room setup (Advices accepted)

Strain: Big Bud (Fem)
Space: DIY PVC Tent 5000 x 3000cm
Lights: 8 x 600w Dual Spectrum
Vents: Cool Tube (need more advice on this)
Co2: Maybe?

I need advice on these things:
- I am making DIY pvc tent that will fit the room it is in
should I paint the inside with plain white color
or cover it with mylar foil for reflection?
- How will I redistribute lights?
Should I make one single reflector and fit all 8 x 600w inside,and run a cool tube through
or should I give each plant own 600w above it without reflector (considering all tent is coated with mylar
and run more fans inside with negative pressure

Any advice is welcome,thank you

My mistake,it is 500x300
I will make another thread,mods can take this one down