How to update search scope rules programmatically

I'm changing my content sources to contain multiple web applications instead of one web application per content source. I currently have rules set up for my scopes to use the corresponding content source. I need to change this to use the new content source and add a rule for the URL. Since I have hundreds of site collections I'd rather do this programmatically.
Below is the basic outline of how I'm doing this.

  SearchContext context;
            using (SPSite site = new SPSite("http://hostheader"))
            {
              context = SearchContext.GetContext(site);
            }
            Schema sspSchema = new Schema(context);
            ManagedPropertyCollection properties = sspSchema.AllManagedProperties;
         
            Scopes scopes = new Scopes(context);
            ScopeCollection allscopes = scopes.AllScopes;
           foreach (Scope scope in allscopes)
            {
                if (scope.Name == "scopethatneedstobeupdated")
                {
                    try
                    {

                     
                        ScopeRulesEnumerator sre = (ScopeRulesEnumerator) scope.Rules.GetEnumerator();
                        while (sre.MoveNext())
                        {
                        
                            sre.Current.Delete();
                            sre.Reset();
                            scopes.Update();
                        }
                
                    }
                    catch (Exception e)
                    {
                    
                        Console.WriteLine(e.ToString());
                     
                    }
                
                 
                
                    scope.Rules.CreatePropertyQueryRule(ScopeRuleFilterBehavior.Include, properties["ContentSource"], "newcontentsource");
                    scope.Rules.CreateUrlRule(ScopeRuleFilterBehavior.Include, UrlScopeRuleType.HostName, "http://hostheader");
                    scope.Rules.CreateUrlRule(ScopeRuleFilterBehavior.Exclude, UrlScopeRuleType.HostName, "http://allothers");
              
                    scope.Update();
                 

                }
         
            }
            scopes.StartCompilation();