[innerbooty]

Thanks for the reply! As far as I understand it (I may well be wrong) High Sierra is the highest I can go on the 2009 Mac Pro - even flashed to 5,1 - without upgrading the processors.

And yeah, I would ideally like to stick with the Apogees, unless there is a compelling reason to spend the multiple $K to upgrade.

I think I will gain more by upgrading my monitor/mix section. My console right now is a Soundcraft Ghost, which is old, and is having all kinds of issues. The question would be what to upgrade to? Don't need 32 channels, that's for sure. SSL SiX? Wish it were the SSL 12 or something like that. But that's a whole other thread topic... Thanks!