Hey Grizzly you have to kinda read the plants to see where they want the light. Seedlings dont need much light for the first couple of weeks. If the seedling starts to get tall and leggy looking then it wants the light closer. If it curls up on the edges or doesnt get taller and get any space between the nodes then it either has heat/ light stress. That means the light is too close. With that being said they look pretty happy right now. I would move it down about an inch every couple of days until you get to 24 inches and let it run there while you monitor what they are doing. You can then decide of you want to go closer. Learning to read what your plants are telling you is the most valuable skill you can learn in this hobby. Hope this gets you headed in the right direction. Good luck