Hey Stynky.....What you said was exactly what I suggested as in lights down the middle with maybe 1 plant on each end like Dabs has goin in his thread......but.....with the screen "behind the plants....To be honest, if I had 3 lights to work with and that sized space I'd stick em all down the middle and slap chicken wire around it. I believe those dimensions will give you about 6-8 plants in 5 gal pots around the ring and you should still have scooting room around the edge. Then just put it on a drip system and you're golden for a damn near fire and forget harvest. I don't wanna say anything I shouldn't, but I've known some REAL out-there people in my day who grew and they pretty much all did it somewhat like that because it didn't matter how strung out they were during the grow, they'd still usually get a harvest as long as they remembered to change the res every week or so.
The whole ideal WSF thing doesn't really affect this kind of ring either, since you can just wrap the thing in plastic. Make a few posts out of 2x2s and wrap panda plastic around the outside. $30 and your 7x7x7 box just became a 6'x7' cylinder. Then you can just take it down once your plants grow into the space.
As a disclaimer, I hate doing big trees in small spaces (of the more-lights-than-plants variety). Tried it and couldn't stand it. Makes sense if you're trying to run something big by yourself or if you're trying to get around MMJ law enforcement but that's about it. I think it wastes too much light to be worth the extra effort over plain old horizontal lighting and trays. That's just my opinion.