Within the Layout Designer feature on your network you are also able to set the shape that you would like to use with your RSS Zone. To change your RSS shape you will have need to have added at least one RSS Schedulable Zone to your layout design and then use the various shapes available on the RSS Design tab.
As you will see there are six different shapes that you can use for your RSS zones and when added you can resize the areas in the normal method of either using your mouse or select the zone and then use the Layer Basics tab as you would with any zone in the design.
You can also alter these shapes with use of the Corner Radius slider that is available. By selecting your shape and then using this slider you can create a whole new series of possible shapes that can be used.