I had a 16" unshrouded puller on a large radiator (33x15x4, 10 core) and the puller couldn't do the job. Rated at 2200cfm. I didn't have room for more puller fan due to the thickness of the radiator, the supercharger on the front of my engine, and the swaybar in the vicinity.
I changed to twin 14" spal pushers rated at 1730cfm each. I ran two 10ga wires to the fans and they run on independant relays. Each fan draws around 15A steady-state but spikes at power-on to 25+A, so make sure the relay contacts can handle that. Yes, you can run smaller wire...but if you want full output from the fans, don't run smaller wire. Why? The smaller the wire, the larger the series resistance of the wire and the less resulting voltage at the fans. You could run 14ga wire and it wouldn't melt...but it also wouldn't give you more than about 11V on the fan with a 14V (engine running) electrical system. You'd lose 10-20% of the fans effectiveness right off the top due to not running it at full voltage.
The twin 14" spals keep the water at 180 (thermostat temp) regardless. So, depending on your radiator geometry, twin pushers could be a whole lot better than a single puller; it certainly was for me.
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