Depends on... Everything. if the plant has all the space it needs, I would personally be happy to get 3-4 ounces under those conditions. But there are infinite numbers of variables, so all I can do is guess.
Well, I have been doing a two week step down in nutrients, and the last week is just pH adjusted water. The step down is important, IMO, because if you just suddenly go from full nutrients to zero nutrients, the plant will hold onto lots of nasty stuff because they sense starvation, and so even a three week flush of straight water can be useless. They can look yellow and clean, but taste horrible.
However, if you gradually reduce the PPMs from highest down to zero over the course of two weeks, the plant has a chance to use what it has stored, and has the nutrients (even in these diminishing amounts) that it needs to continue ripening and using up stored elements.
If I am feeding at a high of 1000PPMs, and I want to start the step down, I will feed at maybe 800, then 600, 400, then hold at 300-400 ppms until the last week, at which time we go to straight water.
Hope that clears it up