hope you dont sleep in there with CO@ and the smell. good luck getting the neighbor to be quiet about your grow when he smells it
Wow, nice and positive.
I would section the closet off into two parts, one side for veg & the other for flower if it were me.
But three 600 watters in there would be badass. IMO 24 plants is way to much for that space, I'de scale it down.
Also what about heat in that confined space, you'll have to exhaust it into the attic/outside.
As for Co2, I use these Co2 generators (mycellium mass) called Exhales, which won't produce enough c02 to kill you but they'll help out.
As for the smell I see you already have a scrubber which I'de run in the closet 24'7. Also buy another inline fan to exhaust all the heat from each cooltube out of the closet & room.
I hope you don't plan on sleeping in there
it'll be loud if not done properly.