One big plant vs 4 smaller plants?

It depends if its run from clone or seed too, I would do a nice clone if you do 4 plants. Should be quicker. I do big plants, but that's because I can't have a bunch. Over time you are better off with small plants. Plus if something happens you have backups. I really love the ease of only taking care of only two plants per 4 foot by 8 foot tent but it is risky. I would just keep it to 4 plants in the square area. I did 2 plants in a 3x3 and it was awkward to train and I had gaps, so I got another 3x3 tent and did a single plant in each. I say give it a try and see what happens it should only take about 8 weeks veg to fill with one plant in the 100cm tent it did 110 pots though. The roots filled every bit of them too. 50l will be okay though

Veg longer = bigger yield regardless of pots. Thing of note is that when I used 5-7 gallon pots I found because I used a airy medium that whenever I tried to push my plants hard they would start to dry out a little faster than I'd like. I personally find my time limited and cannot make more than 1 visit to my grow in 24 hours. This often left the last 3-4-5 hours on a long 19 hour veg cycle often in a state of mild drought. Nutrient can only uptake where water is present. Think of it as losing production hours, time is yield. Bigger pot worked well for me allowing longer periods between watering whilst still pushing plants to limits of what it can handle and not run dry. Not much noted differences with yield.

You'll have a shorter vege cycle with more plants. More pots generally mean more work but 1 vs 4 isn't much of a difference. Yield -- dli and size of plant(s). if the whole area is covered and not too small of a pot and fed properly (i.e. all other things assumed to be competent)... yield is mostly a product of DLI. 40-60g / sq ft is a good goal to shoot for with ambient CO2. It doesn't matter if you have 10 plants or 1. Fewer plants take longer to grow and fill the space, obviously.

Depends on the stain. their is extra security in 4 plats as if one fails or dies for w/e reason it is not a total loss. One big plat is easier to care for though in the sense its just one pot your watering and feeding. 100x100x200cm is around 3'x3'x6.5' tent. I would say do 4 plants. I do two big plants in my 2x4x6.5 and they do well. its almost the same surface area. 8ft squared vs 9feet squared. The only main diffrence is the shape. Square vs rectangle. Rectangle is easier for 2 side by side. but with a square id want one in every corner to maximize the light usage. Could use LST and HST to train them but if they autos HST is not recommended. Good Luck!