Building my first grow cabinet.

What's up guys and gals? I've been lurking around here for awhile collecting some good information. By no means am i a pro grower. Im pretty much a noob. I've had 2 successful indoor grows, one was 2 sour diesel and 2 sfv OG kush and the other grow i just finished up was 2 bubba kush and 2 sfv OG kush. and one 10 plant outdoor grow going on right now as an experiment. Im currently 2.5 weeks into flowering my current indoor crop of sfv og kush. well i loved the OG so my next grow is going to be 4 sfv OG kush. they are just growing in my bedroom closet now so i wanna build a cabinet on my sun porch.
One of my buddies gave me his 8 site aero cloner for free. its just like a 5 gallon bucket with a pump and sprayers, but i was like hell yea that's a score. and a got 5 cuttings from my other friends SFV mother plant. 1 for my mother plant and 4 for my next grow. My plan is start cropping out 4 plants per month. I put them in my cloner 9 days ago.

So what I got is a 8' x 8' sun porch hanging off my master bedroom ( my house is all 2nd story, the garage is the first floor) there is nothing above, below, or on 3 sides of this room i plan to use. the only thing i use it for now is storing my hunting and camping gear. It is insulated, but there is no duct work going to it so its not a climate controlled room. No one ever goes in there. Here is the side of the room my cabinet is going to go in.
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This is a sketch of what i plan on building for the that room.
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And here is a drawing with all my planned dimensions.
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Lights i have are a 400 watt HPS for the flowering zone, 2 - 35 watt 6500K CFL for the mother plant/ clones, and 4 - 4' long 35watt 6500 kelvin fluorescent lights for the vegging zone. I have a fan out of a air filter that is a centrifigal fan that moves quite a bit of air, it draws air in from both sides.

I think my cycle will be 2 weeks in cloner, 5 weeks vegging, and 10 weeks flowering. (approximetly).
Some questions i have before i start construction.

1. If I have my cabinet pretty much sealed up will one fan be enough to draw air through all 3 sections? maybe a couple small oscilating fans inside to help keep air moving.

2. Im pretty sure im going to leave the cloning/mother sections one open section. Is this ok? can i run my mother plant on an 18/6 light cycle and then change it to 24/0 light cycle when im cloning, and then back to 18/6 when my clones go into the vegging zone.

3. My last sfv og ended up being 38" tall (not counting the pot) in a 3 gallon pot. But i just aquired 12 5 gallon flower pots for next to nothing that im thinkin about using for my future grows. I also plan on LST for all of my future plants. Do you think the space provided by my drawings are large enough to accomodate 4-8 LST plants in 5 gallon buckets? btw im thinkin 3.5'-4' tall for the cabinet. i havent decided exactly yet. what do u think? shorter would be better so it doesnt block my windows that much in that room..

4. It's pretty damn hot around here right now so i was thinking of ways to cool down the room. its hot now, its going to be even hotter with all the lights on. One thing i was thinking of was how race cars cool down there fuel when on the track. the have an icebox with their fuel lines running through it and just pour ice on it. so i was thinking of upping the size or this. using a big cooler with as much 4" duct work as i can fit inside and still get a bunch of ice in there and just draw air through the cooler then into the grow box. i figure if i get a good enough cooler that will keep the ice frozen it might work ok semi decent? i donno im just kicking around ideas of how to keep it cool. I dont want to spend $100+ on a window a/c unit if i dont have to. it would only need to be during the hottest hours of the day for a few months out of the year. any other time its 70-75���° F in there. or below, in that case i can just use a space heater to warm it up if i need to.

5. Will my air path be ok traveling through each section? or should i make each section have its own air inlet from outside fresh air.

im going to make the frame out of 2x4's and cover it with 1/4" OSB then paint the inside flat white. gaps will be sealed with duct tape and caulking and the door is going to be sealed with weather stripping. it should be fairly airtight except for my air in and air out.

i may have more questions.

Why not just build 2 tents with pvc and black/white poly?

Also, you can just take cuttings off your plants as you move them into flower...no need for a mother.