You can query the page size propeties via code and you don't have to parse the XML. See the following link which contains a VB.Net RS script:

http://www.developmentnow.com/g/115_2005_10_0_0_616192/Probs-running-script-to-fix-linked-report-page-settings.htm

Converted to C#

ReportService2005.Property[] pageProps = new ReportService2005.Property[6];

pageProps[0] = new ReportService2005.Property();

pageProps[0].Name = "PageHeight";

pageProps[1] = new ReportService2005.Property();

pageProps[1].Name = "PageWidth";

pageProps[2] = new ReportService2005.Property();

pageProps[2].Name = "TopMargin";

pageProps[3] = new ReportService2005.Property();

pageProps[3].Name = "BottomMargin";

pageProps[4] = new ReportService2005.Property();

pageProps[4].Name = "LeftMargin";

pageProps[5] = new ReportService2005.Property();

pageProps[5].Name = "RightMargin";

pageProps = _rs.GetProperties(string.Format("{0}{1}/{2}", _mainFolder, _masterFolder, MasterReport), pageProps);