I know its your first but look into either ScrOG or LST. Do not let your plants get more than one foot tall, as some have done to their demise. I think its so silly to see a 4 or 5 foot plant under an LED setup, hell, I wouldn't let mine get that tall with a 600 hps. Stake it down, try to spread her flat.
I did notice its a cabinet, so height, maybe heat will be your only problems.