Hey man--did you ever get much feedback? I'd say, on the outside, as a guess, you might have topped too early. The plant seemed a little reluctant to take off in a hurry, then I think pruning it like that sort of interrupted the development at a crucial stage. Did you read anything about TERMINAL BUDS in a grow or horticulture book? Plants have a flow of energy and nutrients going in the growth and flowering/fruiting processes. Snipping the top or end bud off a plant sends a chemical signal to try growing below the cut off spot. That's why you prune hedges to make them thicker and why trees growing in harsh sea winds always look tight, cropped and low. This may explain the plant's 'stuntiness', if you will.
I didn't read too much in-depth, but you said something about using (only?) 2 15 Watt tubes, right? The amount of light those are giving your plants is, I would say, insufficient. Are you moving on to more powerful lights soon? Also, what's your soil like?
I have grown a bit before but am very much a newbi/hobbyist, but I've always been a gardener, so plants make sense to me. You sorta sounded like you were in serious need of info, so I'm just saying what I know.
Ask away if you find this helpful.
Dray