DLI/PPFD for autoflower seedlings on a 24hr light cycle

DLI is a rose, is a rose, is a rose. 35-40 dli in ambient co2 conditions is probably near max for vast majority or people. if your garden has elevated CO2 and you tightly control temp/RH, then you can go much higher. even with ambient co2, temp/rh control matters of course. 35-40 dli over 16 or 18 or 24 hours is no real difference. in fact, you'll have better results if you give some amount of dark time as opposed to 24/0. you are trying to force feed your plant, and all it wil do by giving more is build up a resilience to the light.. chlorophyl cannot produce more sugar than it is capable of per 24hours... so it's just shoving excess energy down the plant's throat as if it were foie gras. just as an outside plant builds up rsistance to the sun. a plant can* build up resistance to too strong of light... or you may stunt it or damage it otherwise. even if it looks healthy your just throwing electricity down the drain.