well depends on the watts of the cfls and the t5's, it is said that 5,000 lumens per square feet is enough.

While jorge cervantes says that 10,000 lumens per square feet is what you want.

I have one plant under 12 26w 2700k CFL bulbs and i still think its not enough.

Note: that this plant is inside of an 18gallon bin

edit: oops just saw that your setup was 2' by 4' i would definitely look into getting more bulbs for flowering as you will not be happy with the results unless you increase the lumens