How many girls per 1000w DE HPS?

Keep in mind I am only vegging for 2 months in 5 gallon pots. I will throw into flower when they have reached a maximum of 50 inches in from the base of the pot. I was thinking 4 girls per light. My my goal is to yield 1.5 lbs/ light so to achieve this I will need to get 6 oz per plant. That break down to .672g/w. Achievable?

Only two months? haha I'm lucky if I can go a week. Anyway if you're using the DE bulb @ 1000 W I'd think you'd be able to squeeze in a couple of more? What is your sq. feet available? I'd think you could do a 6X6 with a DE @1K? I only have a 4 x4 available and that DE @ 1080W is too much. I set it at 630 W and do fine with 4 plants.

This will be grown out of a unit 8' wide, 40' long and 8.5' tall.

I squeeze 24 plants under 2 1000 watters in an area approx. 8X10 ft. I've been doing it this way for many, many years. The keys and things to remember are
1. Pick the right strain. Don't pick some monster strain that grows big.
2. Pick shorter plants, and top at least once to control height.
3. Make sure you have your watering process thought out as it can be difficult to water plants in the back of the room/tent.
4. Don't veg for more than 4 weeks, and maybe consider a bit shorter than that.
5. Plants jammed in tightly tend to elongate so be prepared- that's why I top.
6. Good air flow is essential to stop mold, PM, etc. make sure you have good fans and exhaust system.

Lastly, many times I've had to rip rooms apart as plants fall into each other, crowding, mite control, etc. I now use tomato cages- 3 footers- which help. And keep lights high enough so plants don't burn.