Hi
@HolySmoke! I like to dim my driver to the max as soon as my plants enter the preflowering stage. If you have only 1 or 2 plants in here, there's no need for more than 400w during the veg stage, but it's all about the quality of your light/spectrum and the way you manage the plant-to-lamp distance. I would keep it in 400w mode until you trigger the flowering stage. Hope this will help, let me know in the comments section if you need any further information. Happy growing! 👊