You will get the biggest plant by starting in bigger pots and not transplanting a bunch. Those roots closest to the stalk are small when it's growing now but months from now the roots closest to the plant will be giant to support all the roots coming off of it and that main root ball will choke itself. Hard to describe in words.
So if you crack a seed and then put it directly in say a 7 gallon, that main root ball is more spread out and not all jumbled. Then you plant that directly into your final outdoor container/hole at the beginning of summer. It won't choke itself later. If you are growing monsters it's night and day. If you transplant a few times and the roots have touched the sides of the pots and changed direction more then once, they will never do as well.
The multiple transplants are for indoor growing. Not for growing very large plants that are grown for 6 months. I have seen the side by side differences for years. This is ONE of the reasons that plants started later seem to catch up with plants started earlier.
Don't take my word for it. Do a side by side. Watch how much bigger the plants get. Then at the end of the year dig up the roots and look at the structure.