thats a scary situation to be in. If I were you I would get some ssds in raid(M4's) as your win/apps partition and use 2 of the greens in mirrored mode for your backups. You can run your 4 greens raid 0/1 but its not worth it. I've lost some valuable data this way I will never get back. just get some m4's in raid0 and mirror the data drives. maybe take the other 2 greens and raid0 those as a medium between your ssd set and your critical data set. you got it?

set A. ssd raid0 set B. 2 green raid0 set C. 2 greens in mirrored mode for redundancy.