Electric fans can be either mounted in front of the radiator to push air through the radiator or behind the radiator to pull air through. Another plus is that it will flow more air through your a/c condenser at low speeds increasing the a/c's efficiency. No horsepower loss and they can be operated with the engine off. Naturally all fans are not necessary over 40 mph as the air forced though the radiator exceeds what the fans are designed to flow. My fan story is last year the clutch fan exploded at 40 mph in my BMW 750IL . 15k damage to the maf's( it has 2 of everything, V-12) air boxes, wiring harness, radiator, tank, as well as major hood damage caused by the fan blades trying to exit the car. BMW replaced the manual fans for electric fans the following year. The positive thing is that I took the insurance money and bought a 2006 Dodge Magnum R/T Hemi powered wagon. I love it.
The point is, there are pluses and negatives for every thing you are looking to do. Make your choice and pay the man.
Oh hemimets, I believe the purpose of the solid spacer test is to see how much air a solid spacer verses a clutch type fan will flow.