Ahhhh I see! Yeah it will take a slight bit of time to get used to the forum and gain permissions. You found the right place to gain information and reach out for help though brother.
I’m not an expert in any category by far. I only have one successful grow under my belt, (God it feels good to say that though!) one that I killed because I over watered the seedling, and one grow that was really healthy but turned out male.
One thing I noticed is you didn’t mention anything about what you will use to test pH or TDS/EC.
I recommend the Apera PH20 for pH and EC20 for EC/TDS.
I’m not familiar with that soil, but make sure you won’t need nutrients too!
I can personally second this statement. Autos can be more sensitive to nutrients, and you cannot control them the way you can with photos. You can keep a photo in veg for as long/short as you want. I’m going to make use of this phenomenon with my cannabonsai grow that I have started. In order to keep them short, I will be flipping to flower earlier than normal.
Literally the only thing you have to do is switch your light schedule. If someone is smart enough to go through the rigors of a grow, they are certainly smart enough to simply change a timer from 16 hours to 12 hours!
As for the light, Spider Farmer is a good cheaper brand but if you can/are willing, go for HLG lights. Don’t think that light will be enough to flower a 4x8 though. Even the data sheet says flowering footprint of 4x4. @dbrn32 is the resident light expert.