Upgrade from 150 HPS to a all in one box!

Heres some plans you guys can critique and hopefully help me.

Grow box will have frame built out of 2x4's and completed with standard 1/2" plywood painted white

Grow box: 3'Dx4'Lx4'H

Mother/clone side: 3'dx1'Wx4'H Lights: 2-2ft fluros with 1 pc fan for intake and 2 for exhaust

Bloom side:3'Dx3'W'4'H Lights: 250 at least preferably 400 watt depending on heat (Will be 9 sq ft) If 400 watt it will be floralux OR bulb alone without reflector

Ventilation on bloom side: exhaust:4" fan with built in carbon filter,Can be upgraded to 6" fan/filter if need be for heat,Intake 2" or 4" depending on exhaust that is chosen and also there will be a small oscillating clip on fan moving the canopy

Soil: miracle grow that feeds up to 6 months in 2.5 gallon pots (It works for me so im gonna continue to use it)

# of plants: 5 in 2.5 gallon containers

Nutes: General hydroponics

Co2: Homemade with sugar and water and all that

Of course it will be on timer and at right kelvin and cri PH etc...I got all that down. Below is my questions.

Do you think drywall would work better than plywood? I was also thinking just putting 400 watt bulb without reflector in box to lower weight if drywall would suffice.

Do you think a 4" or 6" fan with filter for bloom exhaust?

I'm thinking 4-6 oz dry in this box,What do you think?

IYO should i LST or scrog due to height issues or should I be ok if I flower at 8"?

Thanks guys and I hope someone helps me with these questions when I wake up.

P.S. I'm not a new grower I'm just new to a all in one box and I'm upgrading from a small 150 watt HPS grow.

Nobody huh?

Well, I can already tell this will be a long reply so I apologize in advanced lol...
here goes:

-Plywood is better than Drywall/Plasterboard, but Drywall/Plasterboard insulate sounds and heat better.
-Make sure you treat your plywood to protect it from moisture or any spillages/mistings (even if you paint or line your box with reflective material).
-I'd keep mothers and clones seperate, as they prefer different conditions.
-If you want 400w you will likely need a cooltube, maybe even for the 250w... Conditions where you are will affect your grow temps, especially in a small box.
-Use a reflector dude! If not you're only using half the light (get a 'double parabolic').
-The more exhaust the better... within reason lol. Fans Lose almost 60% airflow through a carbon filter, so take that into account (Pro Filters, not sure about DIY ones). 4" in 6" out will be fine.
-I'd do LST into SCROG. Height should be fine if you SCROG. Remember plants can up to triple in size when flowering, so whether they grow up(h) or in a SCROG(w), they will need space.
-Yield seems realistic... all depends on conditions, and investment of your time and money.
-I'd start in the smallest pot you can find, start LST in small pots and slowly work your way up to the 2.5 gal, then start the SCROG (allows root ball to get nice and "chunky").

Finally, I definitely DO NOT RECOMMEND the soil you have!
I know it works for you and I'm not criticizing your technique, but for the same price you can get much better products, and add your own nutes ect.
Miracle Gro ratios are not very good for us from what I understand, and is too hot for Seedlings or Clones, and they will not be too happy...

Hope this helps you.
Happy Building!

Zip