Changing from RAID 5 to JBOD free up capacity? To RAID 1?

Hope this is the right joint. I have 4x 4TB HDD sitting in my EX4100 under RAID 5. The dashboard says I have 4.7TB free. As I’m too cheap to buy larger HDDs, and still have 5TB of media to store, would switching from RAID 5 give me more capacity? Would it be safe to go down to JBOD?

Well, I found the answer. If I change the RAID type ALL data is wiped. Loverly.