Hmmm … seems like you're overcomplicating the storage/backup solution.
But, you're Brad, and you know things/want to learn things.
Otherwise, I'd recommend an
OWC enclosure that you can build out the way you want. Buy the box, make it RAID 5, and install your own drives. They're reliable and fast. With some of them you do also have to get a SoftRAID license, although
this one comes with it (these are the units that we sell and customize for our clients). I think I've built out about ten of these in the last 2 or 3 years. They're easy to deal with, and
SoftRAID works with both Mac and Windows. It isn't "Tinker Town" stuff, but SoftRAID gives you a lot of options as far as RAID monitoring and notifications, etc.
And, yeah, your "oops" are yours!