Microsoft’s Remote Desktop Connection is a nice piece of software. Wondering how to configure a desktop size so that it would fit perfectly into rotated monitor, I found the directions hereto be very simple:
To set a custom display resolution in an .rdp file Open the .rdp file in a text editor. Add or change the following settings: desktopwidth:i:<value> desktopheight:i:<value> where <value> is the resolution, such as 1680 or 1050.
The articles goes into detail about other ways to set the values.