If you want any kind of serious discussion, lookup Grand Master Level on youtube, he goes live often and has demonstrated proven results with defoliation techniques in his videos.
For me I use defoliation to open up the canopy. When plants are tightly packed, they can overlap causing standing water and blocking out much of the light reaching anything below the absolute highest tops. So to remove some of these leaves is to prevent a stagnant canopy and it also helps to allow light onto bud sites which otherwise might not have received it.
I've caused intersex when being too aggressive DURING the stretch, so my advice is to do like GML and wait til they're done stretching, 14 days or more before tearing leaves off, but as someone above stated you might try thinning them out gradually during the stretch..in fact I will implement some of this on the next girls to flower.