Modifying a MRSS Template

I am looking to modify the MRSS template to use one of the other display methods (e.g. "roGridScreen") while still loading from a standard MRSS feed. This is proving to be no simple task. I have tried to build the functionality from the simplegrid application that comes with the Roku SDK but am still having problems. How is this accomplished? Should I decide later that I want to do a different display (basically anything other than a posterboard) what would be the methodology behind tackling such a task?

Any help would be appreciated!