The typical setup I have seen is to wire the fan with an override switch in case the 'stat or thermal switch you're using fails, or just for peace of mind (a 'running' indicator lamp wouldn't hurt either). And contrary to popular notion, the battery is there for one job: Starting. Once the car is running, the alt. is running everything. The idea is the loss from the extra drag imposed by the increased electrical load on the alt. is less that the loss of the mechanical fan. A 'puller' fan is much preferred to a 'pusher' as it dosen't block the airflow, a pusher will cycle more often in the same conditions. A puller will have to be slim to fit in front of the water pump pulley, I will be fitting one I have soon. I will also fit a larger alt, as a fan can draw as much as 10 amps.