16tb Limit - Is that Useable or Total?

apeofjungle wrote:
When I first set up the Pro, is there anything special I need to do mixing the drives that are over and under the 2gb old limit?

I would ensure your running 4.2.17, (just start with 1 disk)
if it's not, then upgrade to 4.2.17 and reboot. then shut down, put all the disks you plan to use in the device, perform a boot menu factory default (see FAQ), configure for single or duel redundancy via RAIDAR, then it will boot up and you can setup your shares etc.

You can add data and such while the device resyncs, but obviously the more read/write you do, the slower the resync will take, and the resync itself will slow down other copying.