More disks == better perfomance.

The 0+1 filesystems will definitely do better than the RAID 5 filesystems, especially if they are spread out on two controllers. As you know, redo on RAID 5 is bad news. Also, I would put your ORACLE Software and TEMP on the single disk and not archive. IMHO, archive is much too important to be NOT protected.

T3's use Hardware RAID, right? Even so, SW RAID and 0+1 will be better than SW RAID 5 anyday.