First time grower, very tight space.

Attached are pictures of my grow space.

It is a 18gal rubbermaid tub turned on it's end.
Inside are a pair of 27w daylight fluro's (1400 lumen each)
and a 3in inline vent fan, both running 24/7 right now.

This is my first time growing, and i'm not interested in yield. I germinated a handful of seeds and picked the healthiest ones to grow, three in the same 8in pot. I'm looking to grow them through to flowering so i can pick out a female and start cloning. I have two questions, really.

First: What is the best way to utilize this small space? I was planning on Low Stress Training.. bending the plants down to the bottom of the enclosure and letting them grow upwards again. Is this the best approach for the space?

Second: When is the soonest i can start flowering? Again, yield is not an issue, i'm concerned with getting a female plant. I'm worried about the three plants overtaking the grow space too quickly, especially when they double in size during flowering.

eventually they will show preflowers, then kill the males. then let the female grow bigger, cut some clones, let it grow for a week more then flower it. you need a second box to grow clones in so you have a new female to plant when you done with the one you just flowered.