Don't mean to disappoint you, but there is no way in hell you will get 16oz from four plants in that type of setup! Anyways, yield totally depends on the strain. Some plants genes will only let them do 1 or 2 ounces and some can get you a pound (16oz) per plant. But even that is under ideal growing conditions!!
Without growing under MH or HPS don't dream too much about ounces..think more in grams otherwise you may be dissappointed.
Anything less than MH or HPS usually produces real tall and skinny plants, thus resulting in long internodal growth. It's called stretch
Compare these two pictures :
That plant is receiving poor lighting. See how tall it grew before it had leaves? Note how far apart each branch is from the other. And note how long the stem of each leaf is.
Now take a look at this picture
See how closely everything is growing together?
These plants that are 17 days old and a few inches high are are much better garnished than the other one that is twice it's age.
This one here (sorry bout the focus) is the one that has stretched the most, but it's not really that bad at all. Nothing to freak over
On a plant that does nothing but stretch for light to survive, you get way less possible bud sites, thus way less yield.
Because of the low light the light can't penetrate through the plants or the buds. It creates very loose nugs, compared to hard dense ones from good light.
The branches and stem are so skinny that they can't even hold the weight of the bud, and they wind up breaking
If you do use poor light, then I would highly suggest atleast toppping the plant a few times throughout vegetation. It'll toughen the plant up a bit and create more bud sites.
Edit : This is a photo I borrowed from Goo(without permission hope you don't mind!)
It shows a plant that has recieved the correct lighting
Short, bushy well garnished, not long, skinny...well you get it
But good job anyways, it's still just fine from somebody with little grow experience.
I was lucky and learned the trick of the trade from experienced growers before even starting to grow. Makes a world of difference. I knew right off what NOT to do. Cept years later I am still learning new things, it's one of those sciences that has endless possibilites!