Help Me Cool Down

In addition to your underdrive WP pulley slowing the fan speed, you may not be building up enough pressure in the system. So fixing this problem is pretty important. If that's not practical, I'd say your next best solution is to switch to electric fans.
Running a remote trans cooler will help. If you run the extrusion style, it can be placed just about anywhere so you don't have to put it in front of the radiator.