If you run 'sx-install.sh --help' then it shows you some usage info. You can either pass the installation prefix and data dir to the install script or just edit the install script variables at the top. That would be one way to achieve what you would like, as you could have one datadir /srv/obelisk-main and another /srv/obelisk-test - I don't know if you need different binaries but it wouldn't hurt as you can test new versions then without affecting the main copy.