Make sure you get a quality bulb. No sense in having all that energy at 2700K. Get the 2100K bulb, and if you have a digital ballast then get the bulb designed for it.
You are being a bit ambitious. A SOG would work best in a 4x4 capacity (5x5 total with a few inches for the plants to hang over the sides. If you packed it tight, I'd say 64 plants (8x
is probably a good bet. Figure 12 grams or so per plant and that's over 750 grams.
I think 7 plants is a good number for a 1000w lamp with a plant in the center and the rest in the shape of a hexagon. You can grow plants to about 3 feet tall and a good foot and a half wide and fill a 5x5 area with bud sites pretty easily. 7 plants would need to harvest 4 ounces per plant to match the SOG setup. Totally possible, but maybe not as easy as the SOG.
I think the 4x4 ebb&flow SOG (or coco slabs) is what you should be looking for. If you get a mother plant and a cloning chamber squared away you can be harvesting every 9 weeks, which is pretty much 6 harvests a year. That's the potential for about 8 pounds a year without too much trouble. Get it dialed right and it could be more.