That's a good article Zarf, raises a few concerns with what I had planned.
So SF-2281 controlled drives are pretty much a no go if you wanted to partition the drive 30/90, if I've read that right.
I'm not sure, If you could partition them 64/56 I see no reason you couldn't do 30/90.
Still if the caching tech can't keep up and allow cached data to operate at near native SSD speeds, there's not much point in expending premium SSD space on it.