I finally use the following format of clientsettings.cfg is OK.
IP:http://:52311/bfmirror/downloads/
__RelayServer1=http://:52311/bfmirror/downloads/
__RelayServer2=http://:52311/bfmirror/downloads/
But no idea how to set Automatic=0 in this format of config file.
Keep in mind, on install the Mac agent converts the clientsettings.cfg file to a .plist and uses that. If you reinstall with a different clientsettings.cft, the existing .plist takes precedence.
The format of the file has to be text only, so you can’t use TextEdit on OSX for example or you are actually using a binary file. The exact binary same file that works on a Windows machine will work on a Mac.