ZFS Best Practices?

Hey all, just built out my second TrueNAS Pool and I'm looking for some tips. My pool is just a general bulk storage for Plex, documents, photos, few game servers.

Pool - Main

mirror-1

6TB

6TB

mirror-2

6TB

6TB

mirror-3

8TB

8TB

mirror-4

8TB

8TB

mirror-5

8TB

8TB

mirror-6

12TB

12TB

mirror-6

12TB

12TB

Few things I'm curious about

1. Is this the right way to do mirrors? I want to be able to swap out the 6TBs for larger drives down the road. If I put all 4 of them...

ZFS Best Practices?