I grow with cobs and can find i get a stretchy start (just got a T5 to sort that out) but they soon sort them selves out... I normaly start my seedling off at about 40% power as well and slowly increase to full power over the 3 weeks leading to the stretch (depending on height, ambient temp etc). That's for both my lights, 5 x 1212's @1400ma and one 3 x 1212's @1050ma with a pimped 3w's reds. I let my plants grow toward the light as I have a height restriction, if I get the training right I look to finish about 16" from the lights but that depending on strain and pheno type. Each plant wants a different amount so you have find that happy medium I've got 2 OG's by fast buds on the go, one is loving the light and getting as close as she can the other i showing noticeable sign of have a bit to much.
My kingdom for quantum par meter...