I was about to ask this same question but my situation is a little different.
I start in small trays for cloning. Then, they go into a 3 qt pot for vegging.
Then, when I move them to flower, I transplant them into a 2 gallon pot.
However, I am wondering of that's worth while. Most of the root growth is done during the clone and veg stage. I don't think the roots grow much once it starts flowering.
Is that correct?
If it is, it seems kind of wasteful to transplant right before flowering.
I used to go from the clones to the 2 gallon pots but I find I have a lot more control over watering with smaller, progressive pots.
Sorry to hijack your thread.