I haven’t tried this in a client startup script, but system.gui.openDesktop returns a reference to the new desktop’s JFrame, so I expect you could integrate the removal of frames’ decoration something like this:
hostNames = ["HostNameThisAppliesTo","AnotherHostNameThisAppliesTo"]
if system.net.getHostName() in hostNames:
# Open and setup top left desktop.
windows = ["Main Windows/Main Window", "Navigation"]
desktop = system.gui.openDesktop(width=1920,height=1080,x=0,y=0,windows=windows)
desktop.dispose()
desktop.setUndecorated(True)
desktop.setVisible(True)
# Add additional desktops with desired windows, size, and location...