You really should put the lights closer to the plants if you haven't already. one of those babies is so tall! you could gently secure the stem to the side of the cups to keep them all the same height but definitely drop the lights to about 2 inches away from the plants or prop the cups up on something and you see them bush out rather than climb towards the light. make sure your lights aren't too hot. they shouldn't be.
I'm wondering though maybe the fact they lived their first few days under a normal lightbulb that could be the reason for the stretching entirely.
anyway, your grow box is pretty cool. i've just started gutting a pc case for a stealth grow box. looking at the size of a pc case, i can't see there being much use for it except for a clone box though.
good work, hope they turn out ok!