If you get an error when creating your SharePoint Search Service Application manually, it is because the manual creation doesn't set the proper permission on the databases created (but the Farm Config Wizard does). You need to add "Database Owner" permission to the following databases for the service account after Service Application creation (using SQL Management Studio):
Search_Service_Application_CrawlStore*
Search_Service_Application_DB*
Search_Service_Application_PropertyStore*
Otherwise you get the cannot connect to the Admin Component error on the Search Management page.
Chris