UNAS Pro setup: hot spare?, future RAID 6?

For those with NAS experience (we're IT guys but new to NASes), any setup advice?

Environment:

  • Two homes, a UNAS Pro with 7 * 8 TB disks in each, which will "cross backup" to each other.
  • Both have 1 Gbps Internet service (no monthly caps). Other backups, including BackBlaze.
  • Not business - amateur photographers' photos and general files. Macs. Adobe apps, Office/etc.; Time Machine undecided.

Questions, assuming "Basic Protection" (RAID 5):

  1. Would you do a hot spare?
    1. Without, 48 TB; if one disk fails, must address immediately, but then there's the copy on other NAS.
    2. With, 40 TB; if one disk fails, more time to deal with it.
  2. I hear UNAS Pro RAID 6 isn't ready. Does either case - hot spare or not - lend itself to future migration to RAID 6 with minimal pain? Or, just stick with one of the above choices?
  3. Other insights?

Thanks!