[carseatdust]

I don't have the answers to your questions, but think maybe they are already out there on the forum. I just did a quick search and came up with a few links to other discussions:

https://www.plantedtank.net/forums/...078889-effect-co2-plant-growth-low-light.html

https://www.plantedtank.net/forums/...07303-diy-co2-newbie-setup-3.html#post9526289

https://www.plantedtank.net/forums/...41-fertilizing-regime-low-light-low-tech.html

https://www.plantedtank.net/forums/...-i-need-dosing-fertilizers-low-tech-tank.html

Perhaps begin there, and see where that takes you. If you get to where you've more specific questions, perhaps take them over to the "Fertilizer" etc. forums on this site, with a link back here so people can see your Tank Journal.

Good luck!