You got your cab for $20 US? Wow!
Oh, I am not a Cab expert in fact I went out and got a Wal*Mart special shorty and just slapped one together rather ghetto.
I wanted to share what i did and I am having hang ups on attachments. I don't see a gallery option? Huh.. new site I have to look harder.
Anyway not to compete with your efforts; Hats Off to you Edwardo Ruffian.
This is a Shorty cab around $50 at Wall*Mart. The reflective is bubble insulation. The floor is the only shelf drilled with 1/2 inch holes and the bottom of the cab doubles as a drip pan allowing in cab watering.
Two 2700 CFL bulbs and three High Energy white 120 watt
equivalent CFL in a bathroom 3 light fixture. The 65 Watt security light shown gave up the ghost 2 days in. Hard to take a disassembled unit back for warranty bummer. So I got the three bulb fixture to replace it.
Just a Clone store library. There are holes cut into the top and standard "Clip Light" work lights are attached to the inside to give the 2700s a reflector each.
Two 4 inch 12V muffin fans draw air from the top. No carbon but I might have to as it can smell up the house just in veg.
I think you have a better system in mind but I thought to share ideas. That's what grow sites do best!