Repetier-host has a setting to specify the "print area". That's roughly the size of the bed.
Note that the printer head can go out of those bounds, in my case my bed is very undersized compared to the printer frame, but this would also be an issue if you had clips or some obstacles in the bed.
Is there a similar setting in Cura where I can specify the "print area"/"bed size"/"margins" to be different from the printer width/depth?
Repetier host settings: