well if yu do the things well and right yu can achieve that amount of stuff out of those
but of course, bigger plants yu get easily more. But i just said you could get that much, but i leave it that way ( so there is a meaning yu not gonna end up whit that much, but easily when things going good, yu would get nicely that much)
So with 400w hps or 600w hps yu can easily grow a yield like 250-800g plant! only there is that thing yu only can do 1-3 that kind of monster.
and i have seen some guys growing and harvested 600g and 1.2kg plants and they started the flowering when plant was only 10'' tall (sativa dominant plant) and by the way indica can run fast too in the flowering period, not so tall but that is the good with indica, it will produce thick bud's and smaller area.. i think yu know that too
and i would flower those, but if yu got room and time, i advice yu to keep veg at least 1-2weeks and then do it. BUT IT*S GONNA BE NICE YIELD IF YU GO WITH NOW::
(of course shitty things happens sometimes with grow, and can take tax of your crop, of course it's possible) i HOPE IT NOT!
PEACE!