Ok I have 4 4x8 trays set up in a line due to room shape total area is 16x8 more like 19x8 because I have 1 foot in between the trays to squeeze in there when needed. I was just going to setup 4 1000 watt hps centered over each table thinking that since the lights will be 5 foot off center from each other they should be able to have some good cross coverage. Would 8 600 watt hps each over a 4x4 area of a table be better. Also I have one of those cheapy $100 4' light movers that I could modify to move all 4 1000 watters back and forth over the 8 foot span. Other info that might be helpful 1 plant per sqft vegged to 12"- 18" depending on strain ebb n flo. Tray filled W/ hydroton 80deg f 50% rh co2 1500 ppm sealed grow room so lights will be in cool tubes. I've already got some mixed opinion up here in bc from some of the old timers but looking for some more input from the www.
I'd go with the 1000's, you just get better yields with them. Problem is one 1000 per 4x8 is only 30 watts per square foot, pretty low, light mover or not. Two 600's over each tray would be a little more, but not enough. Two 1000's per tray would give you 60 which is more like it. If you veg to 12-18", you will, depending on the strain, get plants that are like 2-4 feet high. Those plants will take up more than one square foot if they are robust and healthy. I don't know about hydroton grows, I like rockwool blocks on coco mats so I can move the plants around if needed, and it seems to be needed a lot.
600s! You basically get to split a 1kw light in half, and cover twice as much canopy area. Good growers can get 1.75 pounds per 1k light, or about 1.5 pounds per 600w light. 600w lights are the most efficient, but you have to fork over more cash on equipment.