I will be using 2 clamp lights with 13W daylight CFL's. It tested it and it looks "bright enough" and lights up the entire tank nicely. Can't say if it will grown anything yet as the tank is still not set up but it looks promising.
The problem with spot lights I think is that it will cast the light on a "spot" hence the name. An led bulb with a good reflector should help.
I just hung two reptile deep dome fixtures from petsmart (~$20 each because they look cool) with a 13W CFL in each about 20" from the substrate. I am thinking of getting one more to hang in the middle to give me more coverage and so I can lower the lights a bit to achieve higher lighting.
There's a great thread about using Home Depot clip on dome lamps with CFL's that may be able to give you some inspiration or info. EDIT: Here is the linkMy inexpensive CFL light solution
Last edited by Johnny Tang; 03-28-2013 at 02:10 PM.
Reason: Added link to thread