Lose the wet cloth...If u worry about the humidity being too low them mist your plants with regular water.
Plant looks healthy.
I say, if u can then keep fan on at all times, but you can turn it off when light are off(But make sure that it aint blowing too hard at the beginning, cas your seedling is very small and weak...After some weeks, then keep it on as much as u can, cas this will pump your plant stem rock-solid and strong!!!)
Stay high and keep on growing...