Instead of using custom rdlc files for each report we can use LoadReportDefinition method of report viewer control and pass to it genarated report definition file. Download the example of crating rdlc file on the fly. To use this code copy both files into your web site, and open RMReport.aspx file in the browser. You can specify number of report columns by type it in the url: RMReport.aspx?col=4. See the using report viewer control in sharepoint for more information of using report viewer control in sharepoint.
Good luck.