Lots of great tips! The lights are key and they do seem a bit far. You may want to consider a better bulb. I've picked up some "close-to" full spectrum bulb at Lowe's for about $6 per bulb. If you run an osculating fan, it will help strengthen the seedlings and create good air circulation.
If you hang a silver emergency blanket on wall behind the shelves, it will help reflect the light. The emergency blankets are very thin and sorta look light aluminum foil. Easy to tape on
