A) If you want to run with more Appx screen rows and columns, start the client with the following options:

AppxDesktopClient -rows=28 -cols=110

This will launch the client that has been sized to allow this number of application Rows and Columns. Similar to running a non-24x80 xterm window and running Appx.

B) If you want to launch the client with a different screen font size, that controls the overall size and magnification of the Appx Client screen. You can do that with a different startup option:

AppxDesktopClient -initialFontSize=14 &

This will launch the client using that base font size instead of the default it is currently using. The base font size is used by the client to set the overall Appx client window size and also how to scale all the screens it presents. The screens will be 'zoomed' to fill the Appx screen. Similar to starting to client today and dragging out the border to a different size.