suggestions needed for t5 setup

[smokinreefer]

so the actual usable footprint of my tank is about 20"W x 16"D...
because of the built in overflow, skimmer etc.

so i think a 6 x 24W may be excessive.

any opinions?

should i go with 4 x 24W Tek fixture? about $250 with lots of bulb configuration possibilities.

or

20" Sunpod 6 x 18W fixture? about $400 with only 2 OEM bulbs available.

thanks!