Hello Peter, I came on here tonight to investigate a file access issue and saw your post. You may have figured this out by now, but anything physically related to the printer will be in the printer tab. There should already be two extruders defined in the printer profile you are using. Click the little pencil under the Printer tab to be able to change parameters. Hit the floppy disk icon to save what you changed. There is only one nozzle diameter that applies to all nozzles the printer has. Note: if you do not see the printer tab, then click the three dots up on the right side and click the "Show Printer" line to have the printer tab displayed.
