I'd put it on 24/0 so it has NO doubt as to what exactly it is meant to be doing. A nice hit with SuperThrive and good blue light help. You can even use a slightly higher dose of ST than normal, like 2-4 drops in a gallon. Remember, in early flowering, your plant is already using up its Nitrogen reserves, and part of its re-vegging is being put back on
grow' food.