Check Options to make sure you are not using the FSW setting that was recently added to the game. Using both at the same time gives unpredictable results.
The DarqUI utility gives you an option to move the game window to a custom location. On the Settings page under Frameless windowed client, click Adjust metrics. There are some examples for moving the window to a different monitor in the Help file (click the [?] at the top of the utility.)
If this is not satisfactory, you may have better luck with Aerlyn's
MakeWindowFullscreen app. It handles multiple clients on multiple monitors, plus it will detect which monitor your game is running on, and will FSW the client on that monitor. I'm fairly sure it uses the same API calls as the DarqUI apps.