Dodge, you have a very nice grow going for you. Those are some very bushy plants. Don't worry about stress determining your plants sex, the LST isn't going to force that change, it is called LOW stress training for a reason. You need extreme stress, like way too much heat, light, absolute lack of water, things like that to force sex change. You will have at least 2 weeks to cull your male(s), but since male flowers do show before female flowers you will actually have almost 4 weeks to remove males. However the sooner you can identify them and cull them the better.
Now if I may I have a few suggestions for the future. First I would change your lighting. T-5 lights are perfectly fine fro growing, but as far as I can tell those are the standard T-5 shop lights from home depot. Those lights do not have the proper penetration (intensity) to grow top quality plants. Look into horticultural High Output T-5 lights, they will do you much better. I would also mix up my color spectrum. Having some more bluish light in there will only help your plants growth, it creates a more well rounded color spectrum for your plants to absorb and mimics a more natural light. As was said above, the blue spectrum mimics the summer sun and promotes the health of the vegetative growth of the plant, and the red mimics the fall sun which promotes flowering. But take notice that when you walk outside in the fall or winter the light around you is not nearly as red as your lights are. So adding a bit of blueish light will only keep the light spectrum in your box closer to the spectrum of natural light. I know what Ed's book said, but I don't really care.
That actually leads me to another point, drop Ed's book and advice. I would rather not get into specifics on the board about why (if you would like to know why shoot me a PM). I would look into Mel Frank's books or Jorge Cervantes' books and DVD's; I think those would serve you much better. Also if you are up for a bit of advanced reading there is Robert Connell Clarke's Marijuana Botany.
One last thing I will suggest is trimming some of your growth. You have a lot of growth in a small space. T-5 lights only have about 6 inches of penetration at best, so you want all of your important growth at the top of the canopy. If you trim the excess bottom branches your plants will not be wasting energy on trying to make those bottom branches grow. Your top growth will be healthier and give you better final results. Also the crowding of branches and leaves covers a lot of the growth you want to catch up with the top of your plants and if they are covered and not receiving light they will not grow efficiently.
Also what nutrients are you using?
I hope this helps some. I am looking forward to seeing what this grow produces and your future progress.
