well it's \\.\DISPLAY17 but yes. Every time i use vmmaker in crtemu drivers it incriments the count by 2. no biggie. This is also what mame64 -verbose shows to use. This is how i got it to load mame on the correct screen when launching it maually.
When launching mame (groovymame) manually it will correctly launch to the monitor that is setup in the ini file. Playing from launchbox does not. It's like it's ignoring the ini file.