OSC messages received on
/composition/layers/1/clips/7/video/source/lines/width will drive the parameter directly, which will ignore the in/out points.
You can use
which will make the param move between the in/out.
Relative control is great when you have an operator who only does that.
But with pre-set clips, if you need to play the camera clips for any reason out of order, or someone knocks the camera, your shots will be out of position.
Maybe the device is unable to process the alpha channel. To check this quickly, try the Solid color effect on the Composition, with Show image enabled, and color set to black.
That should work to fool the NDI converter.