I was also thinking i could place some kind of netting around the bulb instead of the walls,and get them to grow there.I'm using 400 watts so i'd probably have to get a little closer to get more efficient..
Okay, lots of good questions here, hope I don't forget any!
First, I run a vertical bare thouie and I don't aim a fan at the bulbs. With two bulbs, I'm running it on a trial basis.
My theory for the trellis is in several parts;
1. Fence holds plants up- the trellis and the plants really act in conjunction; the plants root and stalk locate the trellis cylinder, and the semi rigid sections of mesh keep the plant upright and oriented.
2. Fence holds plants in proper position- in order to capture light efficiently, the distance from the filament to the leaf must be managed as effectively as possible. I'm training these things into the shape of a shoe tree the size of the entire closet door, six feet tall by four full feet wide. Every lateral branch is therefore laid sideways across the trellis, so it curves around the bulb only enough to maintain this optimum distance. It's then vine clipped into place, to cover that portion of trellis. The plant continues to grow up and out during stretch and the branches are all handled the same way.
3. Fence guarantees optimum distance- I built my trellis to be exactly two feet from the bulb on all sides, because I want the plants to be within the 'goldilocks zone' of optimum distance from the bulb, all the way around. If I had it to do over, I might go with a somewhat larger diameter, and indeed I have with the five foot diameter Super Silo. Of course, it has two thouies in it. The growing tips of the plant occur all along the branches, and ALL of them can now be pushed through the trellis, resulting in a great green wall presented to the bulb, radar dish style. And every last one of them is the perfect distance from the light.
4. Fence keeps people out, lol - I mean goddammit people, does it take a special kind of stupid to try and work around HOT ENERGIZED THOUSAND WATT LIGHT BULBS?!?! Or, an I just missing something here? I turn one off at a time, let it cool for 15 minutes, slip a bulb box over it so I don't get it dirty while I work in there, and voilá! Nice and comfy, plenty roomy, no scorching required, lol Burn marks are not a testament to machismo- only a permanent 'sign' Jeff Foxworthy would recognize!
Moving on- I think your trellis should be about 75cm in diameter and 50cm tall. 75 x pi = 235cm, or a little over 7.5' in total circumference. I think you should consider using something like the 2"x4"x50' mesh fencing available at Home dePot, because chicken wire is too small in two ways; first, the Gage is small enough to cut into stems, second, you can't reach through it or pull the plant through it because the holes are too small.
I think the tent will make things harder to reach and deal with, and will cut air flow. If you need it I understand, but it will not help your yield, IME. YMMV, lol
One plant per foot all the way around would allow for seven and a bit. I run just two around a thouie! But I see no reason it wouldn't work, obviously you flip pretty quickly.
Show us what you come up with!