You can use a couple of clamp-on work lights. and clamp them to a freestanding coat rack. Use CFL's. They come in all sizes up to 4000 lumens. Being in zone 8A, it is probably safe to take the trees out side for real light. If you do: take time to acclimate them to the sun light I start on overcast days. Citrus trees are so specialized that the citrus forum is the correct place for this. Its not the lights that are the problem. Its how to install them. That is what makes citrus hard to grow. Your currant set up looks fine. Window choise is also important At winter solstice the sun come up and set south of due east or west that east and west windows are almost useless. You live far enough south that there is no need to worry about changing windows as I do in zone 6A. Just put your trees outside. If you use 48 " tube fluorescents Buy either T-5 or T-8 T-5 are a little better but more expensive T-8 are more common and are often sold very cheap as a loss leader to get you into their store. I saw your thread on LED light in the citrus forum. You got very accurate advice. I believe the two BOZO'S in the T-5 vs T-8 were having fun with each other. I know poncirusguy was because thats me. Another choice would be a floor lamp with 4 or 5 aimable lights.