The bellow sample shows how a wireframe template could be set to leverage a default ID for a page layout. Due to how pagebuilder pages are loaded this is done in the pre-initialization of the page. This has been tested in a min site installation of Ektron, but further development may be needed to implement on a site.
protected void Page_PreInit(object sender, EventArgs e)
long pageID = 555;
pageHost.DefaultPageID = pageID;