Stay with an engine driven fan. It is very difficult to get the same efficiency as an engine driven fan with an electric fan. Electric also requires sensors, relay, wiring... More hassle to build, more potential problems.
With a good rad and shroud, the A/C will work fine with an engine driven fan, too.
If you end up with an aftermarket radiator, you will find a variety of tutorials online explaining how to make your own fan shroud.
