Thanks for the reply - seems the lack of responses is leaning towards it NOT being a common thing to try out.
My situation is both Mac and PC DAW's in my studio and how to not have to "double up" gear on everything. For example, to route audio for tracking on either DAW, I use a Digiface Dante box connected to a USB-C switch connected to both Mac and PC that let's me toggle it between them - works great! Super low latency tracking over Dante to both my Mac or PC. Hats off to RME for building drivers that stable.
I'm hoping for the same with plugins, which is why I asked the question - to take advantage of the UAD PCI DSP power to offload my VEP server to deal with only the non-UA plugins.
Maybe I'll hunt for a used UAD-1 PCI card for cheap to try it out, before diving into a full Octo setup....
Dennis