My Ultimate Grow Cab White Widow Grow

Hey guys, here is my third grow, but first journal. As I type this I have three WW ladies growing nicely just days away from flower and filling a scrog up nicely. They are in my first cab build which I used to learn and get a good system down. Now I am on to what I hope to be the ultimate cab build. Heres all the supplies I got- Hopefully I dont leave anything out:

Metal Storage Cabinet- locks, 4 ft X 2 ft X 6 1/2 ft
-typical metal cabinet 4 shelves etc...

Res is a 27 gallon heavy duty tote from home depot.
- 6, 3 inch net cup pots
- dwc but with a top feed system similar to "superponics" systems other cabs use

Lights
- 400W Dual ballast with hps and mh bulbs
- Air cooled via a completely sealed 6" cool tube and 4 inch fan tech inline fan sucking fresh air from the outside room across lights and back out of cab into the room

Ventilation
- 4 inch dayton blower fan attached to a 2 ft 4" carbon filter set on a timer to run for 5 min every hour
- have an inline thermostat hooked up and if temps ever reach 88 my seperate intake fan kicks in (115) cfm dayton computer style type fan 4 11/16 x 4 11/16

Co2
- co2 levels are kept at optimum via a mechanical timer and regulator/emitter

Ph and Ec
- constant monitoring with an electronic meter

Timer is a dayton line voltage electronic timer that does pulse and cycle timing, and has two outputs...

Fan controllers, electronic timers, etc...

I just finished the build of the new res and will try to get pics up asap.
The cabinet is supposed to be delivered in two days, so Ill get pics up as soon as I can get started.


Couple questions I have:
1: I have the co2 tank regulator and emmiter but what type of tubing do I use to deliver it and where do i place it in my cab (this will be my first time using co2)
2: I have always just used gh nutes and have been getting good consistent results. However, I see all kinds of debate over which nutes are best. Just wanting ur thoughts on which way to go.

I think I pretty much have all my bases covered. If there is anything else I have forgotten please feel free to toss it at me.

Forgot to add that I have a scrog as well