Xrextras-curved-target-container questions

Hi All, I’m using the xrextras-curved-target-container and have successfully adjusted the height and position of the container. But I don’t see width effect it in anyway. I’m trying to make the window/hole you’re looking into smaller width wise. Am I using the right command? I tried radius but didn’t see any effect.

Also, can I apply an image to the back wall, floor and roof of the container, Or just a single colour for all three planes?

Can you share a image of what you are trying to accomplish and or a diagram? This would be helpful to better understand what you are trying to build.