Wow! You're really going for it!
Dry weight is a function of plant size, genetics, quality/quantity of light among other factors.. If the plant isn't big enough in veg then it can't produce much.. I'd say those look like 2 0z plants.. Figure they will double in size during flower. No they won't get very tall. Just picture them twice the size as they are now. They'll probably grow a foot taller or so. You have a good shape going though so don't worry about height. You just want a nice even canopy.
Figure it this way.. you should get .5 - .75 grams per watt of light. In theory, you should get two to 3 pounds with that much light. That's in theory..
It's pretty easy to get two ounces of dry bud per plant in 3-5 gallon pots. When your space is half full with plant material you should flip the lights. Then they will stretch like crazy for two weeks then you just sit back and wait 8 weeks.
I can't see your whole setup etc, but I'd almost say keep them in veg another week considering the amount of light you are running.. you want to get the most bang for your buck. You could switch lights back to veg cycle without much harm..
I saw a plant that was grown with a Viperspectra 600 that yielded something crazy like 12 ounces.
What strain are you growing? Feminized?