For what it's worth...I transplanted from 4", to 6", to 8" then 10" to start flowering. And harvested in the 10 inch pots.

When I transplanted into the 10 inch pots: I cut away about half of the white feeder roots and sliced into the root ball, from four directions with a sharp knife. It's not something I recommend to everyone, it's a Dutch thing. Never lost a leaf, and looking at the roots at harvest, the girls wasn't root bound....imp: