Check the Applications/ASGvis folder, you should see an alias to run the DR Spawner. You MUST use this alias to run the DR Spawner or it will NOT work. Once it's running, you should be able to follow the instructions to use the DR Spawner during a render. It's the same on Mac as it is on PC. Also, when going to render a given scene for the first time, always check what machines are set to be used in the DR Spawner settings, and click the OK button when you are done reviewing them, just to be sure that the information you looked at gets used. We found a bug while working on V-Ray for Rhino, where the machines would not be used unless you looked at the servers that are set, and you click OK.