So got it all installed and working. With large files copies, I used to get a max of 110MB/s between the pools over the network (eg maxing out a single Gigabit Link). I now get a max of 150MB/s, some 36% faster (eg maxing out the single HDD at each end). But as I now how heaps of 10Gb goodness, I also can now kick off a 2nd (or 3rd, 4th etc) copy between other HDD and get another max of 150MB/s per disk.
I've had to twice copy all the contents from one pool to another (40TB mix of large, med and small files). It took almost a week over Gigabit. Just the extra 36% would cut days of that.... but in addition I could kick off a copy (outside DrivePool) for each drive in my pool and such a task would then be well under a day.
It would be nice to have "FreeFileSync" style compare/sync between pools in DrivePool as it could then support a thread per physical drive instead of one per pool.
Note: I started to look at 10Gb when Intel / MS no longer supported teaming / VLAN on their Dual NIC cards under Windows 10. Look like they have now fixed this (MS released patches, Intel has verified, and plan to issue an updated driver in June).