personally, I've only used the 32bit XP and 64bit Vista. hated vista with all of its problems so... yeah. I've never run in to anything that a normal everyday user can't do in 32bit.

as far as customizing the bootmanager icons, I'm not following. when you have everything installed the way you want it, and OS X installed last, the default system will be OS X so when it asks you to "press any key ..." press any key and it will show you in textual format the four different partitions on the drive. you use the up/down arrows on your keyboard to select which you want to boot, then walla, it should boot to that. Unless you are using a specific GRUB bootmanager/bootloader you will not have a graphical interface to interact with at boot.

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