12/1 all the way through 24/0 work well enough that the arguing never stops, that means other factors affect the plant more.
Such as light intensity, the more light the less time needed, all within the absolute min and max of course.
If it is an HID bulb, once a week cooling is effective for prolonging bulb life.
I have now exhausted my knowledge of veg timing. I stay vague, details will come.