How does OverlayOrientation work ?

I find this useful package and trying to use in my project. 

My project is for scanning cards which comes in landscape and portrait format. 
I use the ratio = 1.60 and change the orientation to OverlayOrientation.landscape and OverlayOrientation.portrait.
But I could not get the overlay to rotate 90 degree. 
Is the purpose of orientation for such purpose or I am using it wrongly.