Is this your first grow? Because you're doing very well, you have the right soil, right size pots and healthy looking plants, so give yourself a pat on the back.
If you are planning on having the 25ow red and 250w blue then I'd say veg for another 2 weeks, but make sure all you plants are getting the same amount of light. Also the light needs to be closer, but not to close else the plants on the edges won't get enough! As for your yield, one can only give a ruff approximation, but I got 25g with 1 200w red and 2x 125w blue, no ventilation, 3l pots, standard soil, vegged for 4 weeks and fucked up the flowering, and repeatedly burnt them. Hope that gives you an idea.