The client has commandline flags for forcing certain options to be on, but no flags for forcing options to be off. For example, you can force ssh encryption to be on, but you can't force it to be off.
One idea is to let the commandline settings use the same names as the options in /opt/thinlinc/etc/tlclient.conf --force ssh_compression=0 ..and let all possible parameters be available. That would mean _one_ thing to document and teach per parameter, not one parameter in the configuration file and one commandline flag.
Also note that the --force flag merely overrides the starting values. It doesn't prevent modification of these values from the options dialog at a later time.