Have you thought about LST? Doing this and changing the light cycle now is going to be the saving factor in keeping them short as possible.

Once the plants go into flower, it means they need uninterrupted sleep. Which means NO light can get in your flowering room when the grow lights are off. It's been said that low amounts of light, like moonlight, or even green light will not affect them., but light interference in the dark period will cause the plants to go hermie. So I guess what I need to ask is how do you plan to keep the plants in the dark at "night?"