400w x 2 verticlal cooling, and radius

same results, less product

that's 400w less of light, so expect like, up to 10 oz less in dried bud

but you will more than somewhat lower your bill

no experience with hydroponics

since youve got a rectangular tent, you could try a stadium setup.
Northern Farmer Stadium Grow , Vertical

All things equal though, I don't think soil will increase your yield. Hydro is going to give you a bigger plant in the same amount of veg time.

I am currently using a LP aeroponic similar to the Stinkbud system. It is online to produce maybe double what I got in the same tent, same lights as my soil grow did, so I'd like to stay with it. I can shift the square tubes around to get a 30" diameter circle for the plant sites with 6 or 8 plants. I'm hoping that is about the right diameter. I have dimmable ballasts, 600w, 400w, and 350w. How big a light should I use for a 15" radius? I have some 2x3" vinyl coated fencing I can use to hold the plants from growing into the lights. Wanted to avoid buying new tubes, they don't sell the one-piece caps for the 4.75 tubes any more. I've tried to find 6" tubes, I know SOMEBODY makes them, but can't seem to find them for sale anywhere.

Does anyone here know the light spread of a 400w hps when hung vertically?

If it is recommended that a 400w is good for a 3x3 square in a standard setup, then wouldn't that mean when the build is hung vertically, it would cover a 3x3 wall?

Make sense?

Help? ha ha

RED1966

Check out Pyrex bake a round on google

you will lose yield by dropping to 400's but if grown properly you can gets some of the yeild back by doing a vertical stadium grow. hang the bulbs vertical down inside about 3 feet apart.
directly under the bulbs i will lst the plants to keep the low.

by not using a reflector and the bulb down inside, the plants will get more direct light all around.