I don’t worry about the light schedule with my autos! I start them on a 12-12 schedule with decent success and just let them fill in any empty space in my tent! Whenever I grow them in my flower tent I try to give them more light than they would normally be getting on an 18-6 light schedule so I try to double up on the Light and aim for around 700-800 PPFD while they’re vegging and then about 1200-1400 PPFD when they start to flower with a minimum of 1000 PPFD.