Ahh found you, good luck with it m8.
I grow in a space 3.6ft x 1.7ft or their abouts, using a 600hps and just a 5inch extraction fan and passive inlet and seem to do ok with temps, it may or may not help you decide a bit more on led or hps, Well tbh i just switched back to hps for flowering and led for vegging, cus difference in bud size is massive compared, the led i used was about a 550watt power draw from wall.
Here`s my last grow it was first time i switched over to hps from led and i only didf it last 3 or 4 weeks and difference in bud size compared to previous led grows was massive. Dont get me wrong the led grew nice tastey bud and a fair size too i suppose but its just not hps size you see.