When I used to do 24/0 light I had problems with plants flowering. I am not the only one as I had others tell me the plant will try and flower under 24/7 light eventually and that is without me mentioning to them that it happened to me.
For veg I have done 24/0, 20/4, 18/6, 16/8 and GLR. my favorite overall is probably 16/8 or GLR.
If I had to say one was the fastest it would probably be 18/6. But to be honest it was not drastically faster then GLR. and GLR uses basically 1/3rd less electricity.
In the end though besides the issue of 24/0 causing plants to flower they are all fairly close to the same.
For veg I have done 24/0, 20/4, 18/6, 16/8 and GLR. my favorite overall is probably 16/8 or GLR.
If I had to say one was the fastest it would probably be 18/6. But to be honest it was not drastically faster then GLR. and GLR uses basically 1/3rd less electricity.
In the end though besides the issue of 24/0 causing plants to flower they are all fairly close to the same.