Hey bro. Think you looking for someone to help you along the way.
I'd be more than happy to spend time chatting with you in private message or you can just keep asking Q.
So, for starters, regardless if it's light soil, pre loaded, DWC, it is all the same starting out.( If you are using pre loaded soil though I'd recommend mixing a 1L with coco as the mix might be too rich to start off with.) But regardless you really don't need to apply nutrients until you see your first true leafs sprout, to wet your soil either use water or 2ml/L of root stem pour it in the hole and wait for her to grow. After a few days you can start to feed very lightly. (Only applies to coco or light mix) pre loaded soil different story.
You actually don't even need your light on until they have sprouted but I like to put mine on very low after around 12hrs cause they can pop up fast espically if you germinate, (that's a whole other thing) your many questions can't really all be answered in a mes and even if it was things happen when growing so your plan, well that might not be the plan of your plant. Especially with autos they have a mind of their own. So 45cm away from your canopy for the seedling stage 0Days 5-7 days you want to be hitting between 3-500 ppm ambient water used included. So if water is 110 and you want to make a batch of 500ppm your nutrient mix will be 390 (yea it makes a dif in the early stages). Not so much later on.
But I would recommend if you are growing just to do 1 type if you have a spare dark space to put your photos after 12hrs of light once you make the flip because autos like more than 12 hrs of light. For instance I have 4 photos and 2 tents a 70x70 in a 150x150 and I'm constantly having to change lights and plants around and seal up grow tents. So if you don't have spare time or space to be constantly changing things around I'd strongly suggest to stick to 1 type of pheno (photo or auto)
Anyways idk if I answered you but if you need help feel free to hit me up.