Or you could build one of these I have wired it for a 200w cfl tube bulbs but this design could be easily modified to hold any number of cfl spiral bulbs and there sockets.
The main thing I reccomend though is notice the wiring box on the one end it is to make sure I have safe connections to the cord and then there is another junction within to hold all the wires for each socket you use . Seeing as it is a 3"x 3" by 2"in deep octagon box so you can put a lot of wires in there.
Materials 18"-32" galvanized duct at 6-10 inch diameter opened up into a half circle.
Piece of 1/2" plywood board cut into a sliver moon shape on one end (basically forming a rib) and a half circle on the other end cut to fit the diameter of the ducting you use.
And then the junction box if you want to make a really kick ass one you could put a mogul at each end and then wire in 2 more to each side and then load it with 2 300w and 4 150w this would allow you to mix 3 spectrums at each end .