Thanks for the advice everyone. I was planning to go to 12/12 right from the start since my new stealth cab in construction is a HON 4 drawer file cabinet I got for 60 bucks. They have some awesome office furniture liquidators in my area, so I can get office furniture uber cheap. Anyway, I'm going to split this into 2 chambers each with a 250 HPS, 1 ballast made from the base components, and a relay that switches between the lights every 12 hours. So far, with the preliminary design, I'm looking at 14+" clearance. Eventually I'll install a bubbleponics system, since that can be built with a low profile. I'm hoping to use the whole space inside for the grow and put any wiring, relays, ballasts, etc, on the top of the cabinet which will be hidden by another container. I hope to fit 18 plant sites in each chamber. Overall dimensions for each chamber are 24"l x 14"w x 24"h.
HT