I run plants this big because my favorite strain doesn't like being pruned until she is bigger. I drill holes in the top of the planter and I break the top of my plant about 1 foot from the top and turn it 90 degrees almost then I let it heal. Then I bend the plant completely sideways little by little over a week until it looks like a question mark. Then I start pinching apical branches to get them equal and also I remove the lowest growth (great time for clones).. After she has recovered, indicated by lots of new growth and leaves turning toward lights, I move her to flower.
You should bend her over slowly because she can split down the side of the stalk if you go to fast. But if you go slowly she will grow into the shape. I have done it quickly and split my stalk a couple times and while she heals just fine that branch at the split will suffer. I love bending a girl over they always respond well..