i cant give you an estimate on how well you are going to do because i have no clue how experienced you are.. if you are doing it right, and its your first grow you'd get anywhere from .25- .5g per watt.
if you make some mistakes, but it still turned out okay, then probably a qp.
if you made no mistkaes, and it turned out good, then maybe a hp
if you made no mistakes, and you supercropped, then you will have more.. it all depends
but then, if you just completely fucked your grow, then probably none

so its not a garuntee