What size electric fan?

I don't know if this will help you at all, but:
The fan I plan on running is out of my 06 Dodge Magnum SRT. My radiator is 27x19 surface area not counting the tanks. The late model LX Hemi twin electric fans fit almost perfectly. When mounted the whole assy sticks out 4" from the radiator. I have no idea how much current this will draw yet. Hopefully that wont end my plans.

Here's some pics.