Hello. That is what I do. I do a major clipping 1st week before they go into flowering, at that time I also set up my clones from the bottom branches, I take most of the growth of a lower branch, except the end group of leaves. Yes I know it will send it into shock that's why I do it a week before. Then I just let it grow after putting it into flower, I want the plant fully into flowering before I put it shock again. at the third week I do a final prune and trim, with a good picture of what I want the final shape to be. Most of the streching will be done by that time. To me this is when the plant really goes into flowering. as soon as shock wares off, it bursts into flower. Take off up to one third of the bottom branches and any fan leaves that block light from getting to the lower buds. Please don't take of all the fan leaves, they play a major part in this. And in the next few weeks you'll need to take some more leaves off for light penetration. Hope that all made sense.
Chuck.