Rock Kasbah

First of all, thanks for this great software! I'm using Cool Reader on Windows 10 x64. I have made all the changes I want to my liking, except for one. I am reading Epubs, in Fullscreen mode, and I have changed the settings so that the display is in scroll view (not one or two pages). I want to increase the margins on the right and left sides. I have already set them to the maximum of 9.99% but still the text covers just about the entire screen from the left to the right. I want about three inches...