Lets try to be more .. descriptive!

I'm setting up a grow box ( im a begginer in these things ) and i have this small corner next to a balcony with stairs inside the house that im setting up to be my grow tent, i'm using a 3x2meter sheet of expanded foam pvc for the box itself, and gonna fold it for minimum air leakage, and its gonna have its inside covered with mylar sheets for more reflection and insulation.
I'm just wondering what will be more productive. 2 or 3 plants? for the record, they are auto, LSD-25 Strain, i'm using 75% canna professional plus + soil, 25& perlite, 3 gal smart pots, Biobiz grow/top/max nutrients, and a meizhi 300w LED panel ( planning on builidng a DIY led cob panel the next coming weeks, still unsure if i'll use this on this grow or not as this strain has a very fast crazy seed to harvest time, around 9-10 weeks ), using Ph'ed water at 6-6.1 PH.
I'm pretty sure i have everything pretty much setup, temperature and humidity where i live are not a problem, quite the oposite
Being pretty new at this i think i got everything pretty much ready and been trying to cover all aspects for this small but fun experience!
Anyway here's the plans, everything is to scale and with exact measurments and sizes,
Its gonna be tucked in some little corner that is very discreet. each face of the "box" has a different filling color so at least you can try to understand
Hope you guys have some more knowledge insight so i can improve on the design
Very excited to see this thing going! my idea is to plant them on the 6th of October, New moon here!
Thanks in advance