coco is some bad ass shit. I use it. Dont water that often, coco is a suber absorbant substance and will likely only need to be water every couple days.

20/4 , 24 hours light for the first few weeks are fine. The plant is mostly attempting to develop roots during this period anyway. There is some arguments about roots developing better during the dark. I use about 18 to 20 hours of light for the first couple weeks.

Seeds do not need food for awhile. Wait till you start to see leaves, not the 2 tiny buds that come out with the sprout. Usually at about 2 full sets of leaves you will want to start feeding lightly. 1/4 solution or about 300ppm will be fine for the next week then start bringing it up to about 1/2 solution 500/600ppm. Keep that for veg. Start to up the dosage to 3/4 then full after a week in flower. Depending on your lighting situation, you may even find it usfull to continue with another week of veg in your flower room. Then change the timer to a 12/12 to trigger flower after they have been in the flower room vegging a week while you bring up the ppm to full strength. Make sense? My flowering light (600hps) is so much bigger then my vegging light (T5's) which is why I do it this way.