Select the fan or fans before cutting anything.
Depending on the dimensions of the radiator the fans should cover as much of the radiator as possible. This will take advantage of the entire cooling core.
Some fans a sold with the shroud and some have just a frame.
Also, electric fans are designed to be pullers or pushers depending if they are mounted in back of (pullers) or in front of (pushers) the radiator.
The fans will need to be controlled by the engine temperature.