Just be aware it may change your temps too...which is why I alternate between shelves and light cycles to keep the temps warm. If you grow on one shelf you can alternate one side then the other. Greg (Pic1) does similar. I do believe the indirect light from the other shelf helps and still allows them to recover as well.
My flouros dont put out that much heat. I have had the leaves touching before raising w/o ill effects. I only keep the light about 1" above as well. I dont grow on shelves they are laid out in linear rows.
