Changing output is a must, because surface is the only one that doesn't support scaling.
The problem about fullscreen going back to windowed is very strange, perhaps the drivers are responsible. Try every possible option for "output" in case one of them works for you.
Are you sure 1920x1200 is supported by your hardware? Check the desktop display properties.
Also, be aware that if and when this works, you don't really get higher resolution per se (but you do get better scaling). That is, you will see the image as pixelated as originally in an old monitor. This is unless you also change "
scaler" to anything but normal2x or normal3x; but this only reduces the pixelation of the edges in exchange for blurring the image, and I can't really recommend it. Obviously, you can't make a high resolution image out of a low resolution one. Playing DOS games isn't about good graphics anyway.
Now I gotta go to sleep...
