Please help me with my first grow room

What's up everyone.I plan on setting up my first grow room and have about 4 foot by six foot and about 7 foot height area to work with.I originaly planned on using a 1000 watt mh hps digital greenhouse set up from htg supply but from what I see on some people here such as Dutch master a smaller area with a 600 watt system seems to be pretty productive if done right.I smoke a lot but only myself in the family and am a little stressed on being a little bit lower key and money wise the 600 watt is a little less$What do you guys think and what can I expect as a ball park to produce in these size rooms.Any profesional help would be greatly appreciated,thank you.