Ok I did manage to load it up locally by changing the xml file.
What I see is that the running Nebula 3 in Server mode does still take quite a bit cpu hit on the client (OSX host) machine, but yes it is definitely reduced by running the server on the server (PC slave) machine.
Is there any way to reduce the client cpu hit further you think?
Another problem to report is that I've had a few audio dropouts during mix exports using Nebula 3 in server mode. Audio just cutting out and never coming back during the mix. I am using Nebula 3 though, not Nebula 3 Reverb so maybe that's something I should do?
I did a test just now with the max DSP buffer settings, and it doesn't seem to lower CPU hit to any extent that is noticeable.
By the way, although Nebula 3 Server has a big impact on the Cubase Performance Meter (pushing it up beyond halfway), I notice that in the OSX Activity Monitor the CPU difference isn't great whether Nebula is running or not (about 7% of 1 core difference).