Keeping a multi-story house cool using AC and attic fan?

[FoxtArt]

I'm no AC expert by any means, just two random thoughts from my knowledge:

If your system has return air (it should) maybe reconfigure that to suck all your return from the upstairs. Pull the hot air and it'll replace it with air from the bottom. Idea two is to run a vent inline with the blower... You're supposed to stem them off the sides, top, bottom, etc, a vent inline with the blower (and the end of the main duct) will put out a disproportionate amount of air. It's also not hard to add more vents upstairs on most systems. Cut a 6-7 inch hole in the main duct, sheet metal screw the base, zip tie the inside of the insulated duct to the base, and then zip tie the other end to your vent-duct. Well....as long as you can get ducting up there somehow.... (Those instructions assume round flex ducting since it's a new install)