Well, I can’t remember if it was ifish who said that your plant size and structure is equivalent to your root mass, so it is important to have a good root structure.
I always look for the roots to fill the pot prior to transplanting it. I start with these ones, it is easier to see when they need a bigger pot and you can stick them directly in soil:
I will transplant it to 1 gallon fabric pot (roots are air pruned and they are much easier to up pot) and then to 3 gallon before flipping.
I think starting with bigger pots is just for autos so they don’t stress while transplanting them, with big pots the root will go down searching for water, no horizontal grow.
I water in circles around and ahead the stem so they roots grow horizontally looking for humidity, in soil it is easier as it’s been said, coco is tricky, that’s why i wished you good luck …