If you got room, bigger is better. I started flowering in 10 inch pots, after starting with 4 inch for seedings, then transplanted to 6 inch, then 8 inch. Most people don't like transplanting that much, but I do. I like too see what's going on down below. I used a root stimulator after each transplant, never loss a single fan leaf on 13 plants. Also, I trimed the feeder roots back on the final transplant and sliced thru the root ball with a sharp knife. Nerve racking, but they were not root bound at harvest.....5 feet tall.