CFL or T5 on the same fixture?

I just purchased some fluorescent drop in light fixtures for cheap off craigslist. What would be better to use as side walls in a small grow room about 3' x 4 or 5'? I'm thinking of either keeping it as a 4 bulb t5 setup, or converting the fixture to have 8 CFL's via 4 twin lamp sockets. At the top I'll have my 2x ~100w cfl bulbs in heat duct fixture.