First Leave curl up.

seedlings can be ugly... it'll grow out of it. I wouldn't worry about early blemishes or controtion. Seeds can power themselves for ~2 weeks, so just don't try to kill them with too much "love" early on. some nutes in soil are fine, but it really doesn't need it initially. I see you are in coco... a 1.5ec balanced feed with 10% runoff will maintain a fertile substrate. This is safe from get-go, but prolly better to start a bit lighter on first irrigation, then normal on 2nd. always feed in soilless. always get at least 10% runoff. unless attempting multiple irrigations per day, let pot dry a bit before repeating. top layer will change color. weight of pot at this point is best indicator to learn. unless it falls over or nodes are stacking on top of each other, light intensity is probably fine. A seedling will simply fall over if too much light long before any spots show up. when more robust, top portions wilt in too much light, the spots show up, then quickly spread -> paling of leaves etc.. So, if you observe any stretch, get that light back where it was...