In addition to the settings included in the Parsec application, you can change more settings in the configuration file created in the Parsec application folder. You can access this via the link on the Parsec computer settings page.
The documentation for all of the different settings you can change in this file are here.
Once you change the settings in the advanced settings, you generally need to save the file and just reconnect from the client. If you're making any advanced settings changes to your host PC, you'll need to restart Parsec.