Make sure one read I/O from the filesystem will end up on one physical disk. So the stripesize should be large enough (not smaller) than the filesystem blocks.
Also, since Windows systems before Windows 7 have a stripe misalignment due to incorrect partitioning, you will end up having lower RAID0 performance than possible. If you're using an older Windows version like XP or Vista, you might want to use tools to correct this misalignment. Check google on how to do that, search for "stripe misalignment xp" or something.