Did you do any research on the subject before asking? Because we all know(or at least should know) that the plant builds up energy during the daytime and utilizes the energy during the nights. (grows)
So having that said Why would you want a longer period of light.
I think you are over thinking the growing thing a bit much.
We are trying to mimic nature as much as possible.
Naturally nights get longer and longer. So....
In turn. You would most likely have a smaller crop.
Marijuana starts to stress out after 16 hours of light so. . .
(very controversial subject that conflicts with 24/0)
Anyone that wants to go there can ...
Let the flaming begin.