How do I reduce stretching?

I will give you 2 types of tips: thing you can do now (very little) and thing for future reference. Sounds like you have tried everything and stretch is still a major problem: if you haven't tried yet: do some super cropping, other than that, you could remove the more unruly branches (or top them if you have not done it yet). For future reference: use smaller pots, keep the night temperature as close to the day temperature, that will keep the stretch to a minimum, get the lights closer to the plants, that will keep the plant shorter.