Another thing that I'm considering is just doing this from my linux desktop:
ssh -l astroberry -X 192.168.247.108
Then I can run kstars / phd2 etc and they will use X11 remoting. I should be able to use my giant monitor fully this way without being restricted to 1920.
Either way I've now got a very good system working and I think that I may switch to astroberry from my own home-brew linux system !