My personal suggestion is to not use a double stack cage for a few different reasons. Some debris from the top cage has a way of winding up in your bottom cage. Also the birds on the bottom get stressed somewhat from the activity going on above them. Thirdly, full spectrum lighting is best from the top (from all I have read and personally experienced with my own flock). Would you want lighting shinning in your eyes from the side if you were a bird (unless you constantly looked in the other directions).
Instead of a double stack cage I would use two cages side by side (or one cage with a divider) if at all possible wherever you can find/make room (hang them/it if you have to is my suggestion). Put the F.S. Lighting above the cage for most natural conditions and least stress on the birds.
Aquarium lighting, plant lighting, reptile lighting has been reported in different articles are not being proper for birds. Instead I suggest you purchase a linear fluorescent 4 ft. fixture with good quality F.S. tubes in it. This fixture is your standard white shop-light fixture with downward reflector (can buy in Home Depot) with extension cord that you simply plug into a wall outlet.
Make sure you get a fixture that uses an electronic ballast, not a magnetic one.
F.S. tubes that I recommend and use myself (along with many other members of some of these Internet bird chat boards) are the Phillips F32T8TL950 tubes with CRI rating of 98 and K temp. of 5000 - you can find these and order them on-line, I don't believe H.D. carries them.
For further possibly useful info. on the subject, I suggest that you use the search feature on this board (& on other boards) and read all the posts on the subject in order to come to a decision that is best for your birds.
