What should my light schedule be now?

Easy way: ON/OFF in hours 24/0 to 18/6 for seedlings 20/4 to 18/6 for vegging and flower Some users grow autos under 24/0 all its life, but plants need rest. the down time can help them a lot. I grow in 18/6 for the plants entire life, can go lower to save on hydro as well. even seen 12/12 from seed on autos but they do get a bit stunted in growth. Good Luck!

my simple tactics in mass grows was to keep 24/7 for first 7 days, since seed breaks soil, unless i see big inter nod stretching, then i switch for 18/6 for all veg, when i am happy with size, i change to 12/12 for photo-periods.

Read up on DLI. You'll see it makes very little difference if oyu use a 16/8 vs 20/4 as long as you provide same amount of DLI. If lights are a bit lacking, that is the only time you will benefit from using longer days like 20/4 or even 24/0. Having a dark period is best, but in an extreme situation with shit lights, it might be beneficial to go 24hours. reducing an hour is sometimes just easier than fiddling with a dial or messing with height from canopy. I prefer my height from canopy to set optimal area of coverage -- the geometry of it and distribution of light being the most important factor later on in bloom. In vege i don't mind using height as a dial, though.

15 or more hours of light will prevent bloom phase - technically speaking but may not be optimal. If your lights are very strong relative to area covered, 16-18 hours is plenty. Use length of light, height from canopy and dimming to affect intensity in any way you see fit. Observe and react to plant. If it stretches more, it needs more intense light one way or another. If growth nodes stack too tightly, it needs less. While not as easy on electric bill, I'd rather have more photons flying around than fewer. So, I prefer to use hours of light or height for fine-tuning. I'm sure some contexts exists where exceptions can be made. Raising light will increase light from side with use of reflective walls and reduce light in middle where hotspots might be occuring, but also more wasted electricity than other options. This is pennies in any smaller garden, but could be worth paying attention to in a very large garden. With seedlings and immature plants you are often forced to dim stronger lights. So many 'good' ways to skin this cat.. take your pick. No matter which way you go, you have to read the plant to dial it in. Too many variables exist that make each garden a bit different than the next on top of any genetic differences that relate.