Your folders are full, so hope you see this. I refuse to use RAID, as it is unnescessary. However, the extra Drive bays are used to house hot swap spares, which have never been needed yet, but in a SFP / Gigastudio DAW, one copy of the O.S. + Apps HDD, and one copy of the sample content HDD, is a safe and sound approach to redundancy. They swap out w/o downtime in 2 seconds, where as a RAID array will have downtime during a re-build, or even poor performance while re-building the array, which is unacceptable live.
By using an external DVD, you could have 3 x Scope Pro's sitting in between the front and rear case fans. Just make sure to get a shock-mounted ATA case to protect the 4U CK-480.
Hope This Helps You In Your Quest 4 DAWg's That Can Hunt,