Congrats on your 2nd grow! I just started my first and my Tutankhamuns are about 1 1/2" tall after 4 days. I’m running a 300w led at about 15" currently. I too have noticed the soil drying out quickly and I’m misting the soil 3 times a day. I’m so afraid of overwatering but I think I’m doing OK. I don’t think they are stretching too much yet but I want to give it a couple days. I’m sure the pros will set us straight. Look forward to following your grow! Good luck. Watching
Edit: misread your led height. If your 450 is at 12" and doing well, I may be too far away. Keep us posted.