Ken,
If you mounting the IC core in front of the AC condensor, I don't see any reason to add a pusher fan on the face of it. Since it going to block some of the airflow going to the AC condensor and radiator, I think adding a pusher fan to the AC condensor is a good idea if you have enough space between the IC core and the AC condensor.
I added a low profile 14" Spal pusher fan to mine as part of installing the MP FMIC, to assist with engine cooling. The additional fan made a pretty big improvement.
If you add another fan you don't want to splice into the existing fan wiring or you will overload the circut. You need to buy a generic thermostatic fan controller, 30 amp fuse and a 40 amp relay. Run the main power from the keyed power side of the starter relay and use the relay to turn the fan on and off when it receives the signal from the thermostatic controller.
It's hard to explain without a wiring diagram, perhaps someone has one they can post.
David