NAS Upgrade Help Needed

Hey guys! I hope I'm posting in the right forum.

I work for a photography company, and I'm being charged with upgrading their storage servers. They have (2) 1TB servers (sad I know), and I'm getting rid of those and am purchasing (4) 2TB drives to use in some sort of RAID array.

Now I'm looking to strip 2 of the disks (via RAID 0) to make a 4TB block, and then mirror that with the other drives (via RAID 1). So, I need to know what array would be better and why. 0+1 or a 1+0?

I thought they essentially were the same thing, but I could be terribly mistaken.

Secondly, both servers are using NASLite-2 v2.04 for the OS. Does anyone know how I would then accomplish this task with that? I've never worked with it before, but also don't have a lot of time to sit with it as they're needing this solution ASAP.

I'll be purchasing 4 of the "Western Digital AV-GP 2TB Drive" LINK. Will these be good drives to buy for this?

If anyone could help, and maybe walk me through this in baby steps I'd be forever grateful. I'm looking to have this done in the next week.