Depends on the game you're trying to run, but 512kb was enough for many, if not MOST of the games released during the 1.3 and under era. You don't load WB first and then the game though. Insert the game, turn on your computer and enjoy!
Sounds like something's amiss with your PC floppy hack though. Get a real Amiga drive in that bad boy and make sure the jumpers are correct on both the mobo and the floppy drive.
