New TrueNAS pool for best Reads and Writes ideas

I’ve been running FreeNAS/TrueNAS for years now. And its time to increase my hard drive space. I already have NetApp DS2246 2.5 24bay Disk Shelf NetApp DS4246 3.5 24bay Disk Shelf both with IOM6. so I have the space.
The main thing I do with it is a plex server that I share with a bunch of people inside and outside my house. and some video editing. All my media is on 12 2TB ssd’s currently in a raidz pool. But as we all know movies and tv shows take up quite of space so I’m running out of room. I am looking at getting 8 14tb drives set in a raidz2 because they are so big to store all my media on and use 3 of those ssd’s as cache drives and 3 as log drives. And use the remaining SSD’s as just an video editing and soft storage location.

Do you guys think that is a good way to get fast writes and reads to for the Plex or should I change it up a bit. I am really looking for input on this I have a 14 tb on its way to make sure that the disk shelf will recognize it properly before I go and buy all 8.

My house is full 10gig so that is not a worry.