depends on how long you intend to vege them.
12/12 from seed you can probably fit 1 per sq ft or less. if you vege longer you can fill that entire space with 1 plant
more plants will shorten required vege length, but also more effort -- more transplants, more pots to water, which cna lead to more waste if you rely on any consistent runoff like a soilless grow does. BUT, the electricity save is probably a larger cost... . your time is the key here.. is it convenient for you to do a Sea of Green or not?
Here's what i suggest.. Work backward from area of your space.. you can determine roughly how many colas you want -- assuming you shape a fairly even canopy. i'll try to convert to metric.
1 cola per 15cmx15cm (6inx6in). about 2 colas per sq ft, give or take is a agood target. This gives you healthy sized colas and plenty of breathing room... prun off weak sucker limbs 14-18 days into flower. if a shorter or faster plant, do that process earlier.
So, 25-30 colas in 80x80 tent. divide that by how many plants you have... that's how many colas you want per plant and that will help you decide how many plants to use and how long will have to grow them in vege phase before flip to flower.
symmetry matters too.. growing symmetrical plants is easier than asymmetrical. easier to fill a "square" than an oblong rectangle... the time it takes to fill in the longer dimension of area will mean that the shorter side is probably overgrown.. or short side fills but then long side is lacking. wasted resources and time, if you have to overgrow and prun back.
4 plant with 7-8 colas each would do well. 1 big plant with 25-30 colas would work too. 9 plants with 3 colas each? might be odd to cause that, but math adds up.
sometimes what's best interferes with what you want.. maybe you have 5 strains you want to grow.. so you deal with 5 plants and unusually shaped area of repsonsibility for each plant and just shape them as best you can. But, still work backward from a target number of colas... this helps keep you on track throughout process.
as long as the foliage fully covers the area and abosrbs the most light possible, yield is going to be fairly consistent no matter how many colas you have -- common senns applied.. 1 cola obviously doesn't fit here. But, if oyu chose to really pack it in with 1 cola ever 10cm x 10cm it'll be similar yield jsut smaller colas on each.
Light = yield. total energy (light) = potential growth (yield). If the canopy is sufficient, yield will happen. some benefits to the "right" sized colas.. Large bulky colas look cool but are prone to disease. From what i read the 1 per 6x6inch area is a great starting point. think its technically a bit more than 1 per 6x6 space.. small percennt more. Also, nottall plants will produce bulk buds and trying to do so could cost some minimal yield. the suggestion is a happy medium for cola size.