props for experimenting, but drop the blacklights. they dont do anything, your thinking of UVB light. you get that from those reptile lights at the pet shop. i think they make them that will fit in the blacklight fixtures.
LST - low stress training... bending and tying down branches to attain the canopy you desire.
unchecked, pot grows to resemble a xmas tree. with a primary "A" bud on the top widening toward the ground and growing smaller "B" and "C" buds. with various training methods most growers try to grow a more evenly spread out canopy full of "A" buds.
lumen loss is exponential the further away from the source you get with HID lighting. with your 70w hps's i wouldnt expect great canopy penetration more than 6-10". anything deeper into the foliage will grow airy buds. keep them as close as you can without burning as well. use the back of your hand as a guage, if your hand can take the heat, so can your plants.
luck