I use the botonicare line so I just use 1/4 strength of the seedling chart and keep an eye on them and work up.. I'm still a new grower but that's what worked for me.
I like to give 1/4 to coco as the seed is soaking/germing in paper towel so it has food the minute it pops. Its been said the colydotons have enough energy stored until firat real set of leaves come out but in coco i like to feed day 1 anyways.