I've transplanted hundreds of autos with a 99% sucess ratio. The key is timing and a container that the rootball will easily slide out of. Many on the commercial pots suck, dirt and root stick to the sides. The good quality, round, commercial pots are good, best is yogurt or cottage cheese containers. The plastic is soft and the rootball slips out . I water the plant and wait 5 minutes or so, until the water is absorbed thoroughly. slip the plant between your fingers and flip the pot upside down. With the soft containers, press the bottom like it was a button, to start the rootball moving. Lift the pot off the rootball. Move the plant to its new home! Never transplant a dry pot.
An observation I've made and confirmed is, in a container of 24 to 32oz. a sprouted plant will have a canopy as wide as the container, when the roots first touch bottom, usually 7-10 days. You transplant RIGHT THEN, while there is no, to minimal circling. I guarantee that, if you don't break the rootball more than minimally, you'll see growth in 12-24 hours. No stalling, no stunting.