I guess it depends on how you want them to grow.
This a lousy picture but I am doing a 12 plant single colas grow using 6" nursery pots. The pots hold just under 1/2 gallon of soil.
AK47 & NL clones when they went onto the 22x18 rack. The scrog frame is just under 24x24
As I said, growing one colas each. I had the clones and wanted to give this a try. The frame has the room where I could have let them grow out more. I have really enjoyed doing this one.
Almost a month ago
With the plastic pots and limited vegetation I only have to water every 5 - 6 days.
You can check out Rap’s Sea of Green in cups he is using a tote.