Should I try it without LST in such a box or not?

Unfortunately, my crystal ball does not provide me with the information regarding the size of your box or what strain you are growing, be it auto or photoperiod and with no diary either............ However, placing any plant in the centre and fanning out the branches sideways is a good idea, but bending the main stem to keep an even canopy is probably more important.

Yeah that can work. If the side branches grow well, you can just train those out and let the main stem go up. Keeps things simple and still gives you a decent canopy. Just keep an eye on the main top in case it stretches too much worst case, you bend it a bit later.

I love when people write here that you have to flip the light to 12/12 when we are talking about Autoflowers... So you can see that the don't read your diaries and just won't the poin for the contest GOOD JOB

Like what's been said. Best way is just grow it and if the top is too high just b4 the flip to 1212.. then just cut her level.. easy man... Good luck.. Much love 💚..

Hey there personally when I’m growing in a small tent I like to put 1 plant and let it grow the regular way. If you try and do stuff like using a net and topping the plant a bunch you end up not having enough room I would just let the plant grow regular. Make sure to let the side branches develop some b4 flipping to flower if the side braches are small when you flip to flower they won’t really produce anything if there are a few inches long and sturdy when you flip they will turn into a good solid branch of buds similar to the cola. I would make sure to do lst on the side braches so they are even and produce more.

I am also a "circle" friend. Wouldn't recommend it. It's a lot of stress and more important a lot of work. When I harvest, I also got the impression if I do the angle to high, the branch is a bit underdeveloped because the exchange to the top is hindered. But just a feeling. Anyway, target = light to bud sides. You have a high main cola and then flat circled branches? Why not few branches but at the same height? As you have experience with the genetic, you could try a top (Perhaps ~1-2 weeks before you saw the preflower).