Pound cake auto (2×2 1Light 1Plant)

What do they say? 6 nodes to get beyond seedling stage? I find they need more power a lot sooner than that to avoid excess stretching. The plant's growth dictates... just do what it says. CO2, temp and rh dictate just how much light you can give a mature plant. With ambient CO2, 35-40 DLI "at diode" of a typical LED grow light with reflective walls will be fine at normal hanging distances. umol/s depends on hours of operation and area of coverage. DLI is an apples to apples metric to use. From that point you observe and react to the plant to dial it in based on growth. If you've been babying it, i'd amp up in smaller increments over a short period of time unless any stretch occurs, then amp up fully. I find plants quickly demand more.

Aim for 200-300 μmol/m²/s for seedlings, 400-600 μmol/m²/s for veg, and 600-900 μmol/m²/s for flowering when doing autos.

At that stage i would stay low, around 300-500. Always watch the leaves, if they raise up a bit its perfect, If they claw or/and drop, its mostly likely too much. They react pretty fast on wrong light adjustments, so its easy to manage