Most seed growers advise a continuous 20/4 light schedule for AF's. That being said, I have had good luck by growing AF's on a regular non-AF schedule.
I just finished a grow with 6 AF's and 6 regular plants. I lit them at 20/4 for the first 5 weeks in dirt then switched the light to 12/12 for 5-6 weeks of flowering.
The yield from the AF's was the same as when I grew them on a complete 20/4 light schedule. So, my experience suggests that the light schedule for AF's doesn't
make much difference.
Good luck, BigSteve.