It depends upon how you want your partitions to be organized. This will probably not be entirely accurate but it should be close, can't fin the link at the moment. Starting with disk 0, each Primary partition will recieve a drive letter in order, then each the next disk and it's primary partitions, until the last disk is lettered. The the sam process will occur with the extended partitions. Obviously you can re-arrange the drive letters to your preference afterwards.