Upgrade Process - just have a simple question

Hi there everyone,

Not an experienced user I’m afraid - just a Plex junkie.

So, I Have a 2x6tb EX2 Ultra - almost full now

I want to take these two drives, add another 2 fresh 6tb Red’s and put them all in a 4 bay WD (PR or EX4100 to be decided)

So, my existing drives - do I need to wipe for a fresh RAID install? I’m guessing so. Is there a RAID option that would negate the need to wipe and then copy again? I guess not. I just don’t want to save, and then re copy 6tb of data if I don’t need to. Just need someone cleverer than me to tell me the right way of upgrading using some existing drives!

And If I wipe - just a Windows format? Any file structure recommended? I guess I would be trying to match the two new 6td drives to give me 4 identical ones

Thank you very much in advance for any assistance