At least tell him how. Like for instance say ok "500 bucks gets you these cobs these drivers, but then your going to have to get a high yielding strain like a Blue or a Space Queen and veg for 6 weeks or more, because 2 pounds in a 4x4 is tough to do ask anybody."
sorry i was in a hurry.
i agree, a little more space would help.
most decent strains are not hard to get 1.2-1.4GPY with HQ LED in the 700-900 umol range. the high yielders will cross 1.5 in a well tuned garden. but as mongo said, the space might be an issue
so lets say 1.3 GPW with your average efficiency cob unit
908g/1.3 = 700W
9 cobs at ~75W each in a 4x4 can do this (~1000 ppfd, ~56 g/sf) but a 4x5 or 5x5 would be easier (45 and 36 g/SF respectively)
a safer bet in a 4x4 would be like 500 watts yielding 650-700g (750 ppfd, 1.3-1.4 g/w, 40-43 g/SF)
would need less veg time, maybe 3-4 weeks with some good topping and scrogging
as mongo said its strain (and grower skill) dependent. with the last part being a huge variable so i always recommend a lower ppfd because there is an LED learning curve even for experienced growers