Set default printer and settings in linux?

Is it possible to set the default printer in linux?  On my system I have a remote printer server (RPI/CUPS) for the system wide default printer.  Librecad seems to default to a local printer.  Where and how can I change this?  Is it in ~/.config/LibreCAD/LibreCAD.conf?  Or somewhere else?

This is what I have there:

[Print]
ColorMode=0
FileName=
PaperSizeX=4.096287077673312e-8
PaperSizeY=3.165312741838469e-8

[PrintPreview]
BlackWhiteSet=1
PrintScaleFixed=1
PrintScaleValue=1.56045:1

Obviously the variables PaperSize are weird.  What are the units of PaperSize?  Same as Defaults units?  For letter size, and landscape the settings would be:

PaperSizeX = 11
PaperSizeY = 8.5

?