Demul Problems with Metal Slug 6

Metal Slug 6 is given me problems. When I select FULL SCREEN and V-SYNC on in the video options it won't boot... I get a black screen.
When I deselect V-sync it runs but the games aren't very smooth and you also can see sometimes screentearing (so really want to play with V-sync on!)
Also the Game runs when I select V-sync ON and turn OFF Full screen...

And when I change the GPU plug-in to GPUXDX11 old (instead of the new one) the game boots up fine with V-Sync AND full screen on!! But than I got the problem that some Naomi games won't run...

Is there a way to let Metal Slug 6 Run on other settings than the other games or some other solution?

I Use Windows 10 64 bits with i5 7th Generation and Nvidia 1060 GTX

Thanks for the help!

UPDATE:
I have made a workaround to copy the Demul folder and change there the settings and link the game in Launchbox to that Demul Exe file.
But that means to install Demul 2x and setup it 2x.


Greetz,

A. Potters