This year I was given some seeds from California. Leafy as hell. Many will disagree with me. Once the girl is midway into flowering I will take off as many leaves as I want. I remove the bigger ones from the bottoms and let the small ones stay behind.

Here is an example Pic 1 is before and 2 is after. Pic 3 is the last shot I took of her. As you can see removing the leaves that shade the center of the plant can be done with no long term effect.

If you do this before she starts to bud, or too early, it will hurt your yield. There is no reason the center of the plant must stay shaded for the last 6 weeks. Those yellow leaves can be removed.