Power Mac - Memory configurations

Hey. i've got an old Power Mac G4 Gigabit Ethernet that I'm wanting to upgrade the RAM in. It's got 4 ram slots. Originally it had 1 256mb stick, and I've since added another to bring me to 512mb, but it seems OS X loves memory so I want to give it a lil more .

I only want to go to 1GB for now, but I don't want to close off the possibility of going higher. Anybody know if 2x256 chips and 1x512 chip would work ok, leaving the 4th slot open? (presumably for another 512mb chip in the future)

BTW, this is part of "project upgrade" for this little machine . Aside from the previously mentioned RAM upgrade, I've also modded a PC ATI Radeon 9800 Pro to work in here (I needed DVI out and getting the PC card and converting was actually cheaper than an ADC to DVI converter), and am seriously considering getting a 1.8Ghz upgrade CPU (currently it's dual-500mhz). After that I may opt to grab a PCI SATA controller and add in a 500GB hard drive. Probably would be cheaper to just buy a new machine, but I love tinkering .

Thanks.